Faculty Profiles - YAMASHINO, Takafumi

Papers - YAMASHINO, Takafumi

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Light responses during early day phases of CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and PSEUDO-RESPONSE REGULATOR (PRR) homologous genes in the moss Physcomitrium patens Reviewed

Chiso, K; Yamashino, T; Suzuki, R; Gans, T; Trogu, S; Hughes, J; Aoki, S

PHOTOCHEMISTRY AND PHOTOBIOLOGY 2024.12

Nuclear interactions between the Pseudo-Response Regulator clock proteins and the Multi-Step Phosphorelay mediator Histidine-containing phosphotransfers in the moss Physcomitrium patens Reviewed

Anami, S; Yamashino, T; Kikuchi, H; Suzuki, R; Aoki, S

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Vol. 733 page： 150734 2024.11

A Small-Molecule Modulator Affecting the Clock-Associated PSEUDO-RESPONSE REGULATOR 7 Amount Reviewed

Uehara, TN; Takao, S; Matsuo, H; Saito, AN; Ota, E; Ono, A; Itami, K; Kinoshita, T; Yamashino, T; Yamaguchi, J; Nakamichi, N

PLANT AND CELL PHYSIOLOGY Vol. 64 ( 11 ) page： 1397 - 1406 2023.9

The mRNA decapping machinery targets LBD3/ASL9 to mediate apical hook and lateral root development Reviewed International coauthorship

Zuo, ZL; Roux, ME; Chevalier, JR; Dagdas, YF; Yamashino, T; Knight, E; Ostergaard, L; Hojgaard, S; Rodriguez, E; Petersen, M

LIFE SCIENCE ALLIANCE Vol. 6 ( 9 ) 2023.9

Patterned proliferation orients tissue-wide stress to control root vascular symmetry in Arabidopsis. Reviewed International coauthorship

Fujiwara M, Imamura M, Matsushita K, Roszak P, Yamashino T, Hosokawa Y, Nakajima K, Fujimoto K, Miyashima S

Current biology : CB 2023.2

Diurnal control of intracellular distributions of PAS-Histidine kinase 1 and its interactions with partner proteins in the moss Physcomitrium patens. Reviewed

Kikuchi H, Yamashino T, Anami S, Suzuki R, Sugita M, Aoki S

Biochemical and biophysical research communications Vol. 616 page： 1 - 7 2022.8

A hierarchical transcriptional network activates specific CDK inhibitors that regulate G2 to control cell size and number in Arabidopsis Reviewed International coauthorship

Nomoto Yuji, Takatsuka Hirotomo, Yamada Kesuke, Suzuki Toshiya, Suzuki Takamasa, Huang Ying, Latrasse David, An Jing, Gombos Magdolna, Breuer Christian, Ishida Takashi, Maeo Kenichiro, Imamura Miyu, Yamashino Takafumi, Sugimoto Keiko, Magyar Zoltan, Bogre Laszlo, Raynaud Cecile, Benhamed Moussa, Ito Masaki

NATURE COMMUNICATIONS Vol. 13 ( 1 ) page： 1660 2022.3

Red light-regulated interaction of Per-Arnt-Sim histidine kinases with partner histidine-containing phosphotransfer proteins in Physcomitrium patens Reviewed

GENES TO CELLS Vol. 26 ( 9 ) page： 698 - 713 2021.9

CCA1 and LHY contribute to nonhost resistance to Pyricularia oryzae (syn. Magnaporthe oryzae) in Arabidopsis thaliana

Yamaura Saaya, Yamauchi Yuri, Makihara Motoi, Yamashino Takafumi, Ishikawa Atsushi

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY Vol. 84 ( 1 ) page： 76 - 84 2020.1

PAS-histidine kinases PHK1 and PHK2 exert oxygen-dependent dual and opposite effects on gametophore formation in the moss Physcomitrella patens

Ryo Masashi, Yamashino Takafumi, Yamakawa Hisanori, Fujita Yuichi, Aoki Setsuyuki

BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS Vol. 503 ( 4 ) page： 2861-2865 2018.9

Light-regulated PAS-containing histidine kinases delay gametophore formation in the moss Physcomitrella patens

Ryo Masashi, Yamashino Takafumi, Nomoto Yuji, Goto Yuki, Ichinose Mizuho, Sato Kensuke, Sugita Mamoru, Aoki Setsuyuki

JOURNAL OF EXPERIMENTAL BOTANY Vol. 69 ( 20 ) page： 4839-4851 2018.9

The cereal pathogen Fusarium pseudograminearum produces a new class of active cytokinins during infection

Sorensen Jens Laurids, Benfield Aurelie H., Wollenberg Rasmus Dam, Westphal Klaus, Wimmer Reinhard, Nielsen Mikkel Rank, Nielsen Kristian Fog, Carere Jason, Covarelli Lorenzo, Beccari Giovanni, Powell Jonathan, Yamashino Takafumi, Kogler Herbert, Sondergaard Teis Esben, Gardiner Donald Max

MOLECULAR PLANT PATHOLOGY Vol. 19 ( 5 ) page： 1140 - 1154 2018.5

Diversity of plant circadian clocks: Insights from studies of Chlamydomonas reinhardtii and Physcomitrella patens. Reviewed

Ryo M, Matsuo T, Yamashino T, Ichinose M, Sugita M, Aoki S.

Plant Signal Behav 2016.2

Insight into the mechanism of end-of-day far-red light (EODFR)-induced shade avoidance responses in Arabidopsis thaliana. Reviewed

Mizuno T, Oka H, Yoshimura F, Ishida K, Yamashino T

Biosci Biotechnol Biochem Vol. 78 2015.7

The plant circadian clock looks like a traditional Japanese clock rather than a modern Western clock. Reviewed

Mizuno T, Yamashino T

Plant Signal Behav page： in press 2015.7

Insight into a Physiological Role for the EC Night-Time Repressor in the Arabidopsis Circadian Clock. Reviewed

Mizuno T, Kitayama M, Takayama C, Yamashino T

Plant Cell Physiol Vol. 56 ( 9 ) page： 1738-1747 2015.6

The EC Night-Time Repressor Plays a Crucial Role in Modulating Circadian Clock Transcriptional Circuitry by Conservatively Double-Checking Both Warm-Night and Night-Time-Light Signals in a Synergistic Manner in Arabidopsis thaliana. Reviewed

Mizuno T, Kitayama M, Oka H, Tsubouchi M, Takayama C, Nomoto Y, Yamashino T

Plant Cell Physiol Vol. 12 ( 55 ) page： 2139-2151 2014.10

Ambient temperature signal feeds into the circadian clock transcriptional circuitry through the EC nighttime repressor in Arabidopsis thaliana. Reviewed

Mizuno T, Nomoto Y, Oka H, Kitayama M, Takeuchi A, Tsubouchi M, Yamashino T

Plant Cell Physiol Vol. 5 ( 55 ) page： 958-976 2014.2

The LNK1 night light-inducible and clock-regulated gene is induced also in response to warm-night through the circadian clock nighttime repressor in Arabidopsis thaliana. Reviewed

Mizuno T, Takeuchi A, Nomoto Y, Nakamichi N, Yamashino T

Plant Signal Behav Vol. 9 ( 3 ) page： e28505 2014.1

Transcription of ST2A encoding a sulfotransferase family protein that is involved in jasmonic acid metabolism is controlled according to the circadian clock- and PIF4/PIF5-mediated external coincidence mechanism in Arabidopsis thaliana. Reviewed

Yamashino T, Kitayama M, Mizuno T

Biosci Biotechnol Biochem Vol. 77 ( 12 ) page： 2454-2460 2013.12

Clock-controlled and FLOWERING LOCUS T (FT)-dependent photoperiodic pathway in Lotus japonicus I: characterization of a microRNA implicated in the control of flowering time. Reviewed

Yamashino T, Yamawaki S, Hagui E, Ishida K, Ueoka-Nakanishi H, Nakamichi N, Mizuno T

Biosci Biotechnol Biochem Vol. 77 ( 6 ) page： 1179-1185 2013.6

Clock-controlled and FLOWERING LOCUS T (FT)-dependent photoperiodic pathway in Lotus japonicus II: verification of the flowering-associated function of an FT homolog. Reviewed

Yamashino T, Yamawaki S, Hagui E, Ueoka-Nakanishi H, Nakamichi N, Ito S, Mizuno T

Biosci Biotechnol Biochem Vol. 77 ( 4 ) page： 747-753 2013.4

Verification at the protein level of the PIF4-mediated external coincidence model for the temperature-adaptive photoperiodic control of plant growth in Arabidopsis thaliana. Reviewed

Yamashino T, Nomoto Y, Lorrain S, Miyachi M, Ito S, Nakamichi N, Fankhauser C, Mizuno T

Plant Signal Behav. Vol. 8 ( 3 ) 2013.1

From a repressilator-based circadian clock mechanism to an external coincidence model responsible for photoperiod and temperature control of plant architecture in Arabodopsis thaliana. Invited Reviewed

Yamashino T

Biosci Biotechnol Biochem. Vol. 77 ( 1 ) page： 10-16 2013.1

Molecular mechanisms of circadian rhythm in Lotus japonicus and Arabidopsis thaliana are sufficiently compatible to regulate heterologous core clock genes robustly. Reviewed

Ueoka-Nakanishi H, Yamashino T, Ishida K, Kamioka M, Nakamichi N, Mizuno T

Biosci Biotechnol Biochem. Vol. 76 ( 12 ) page： 2332-2334 2012.12

Circadian clock and PIF4-mediated external coincidence mechanism coordinately integrates both of the cues from seasonal changes in photoperiod and temperature to regulate plant growth in Arabidopsis thaliana. Reviewed

Nomoto Y, Kubozono S, Miyachi M, Nakamichi N, Mizuno T, Yamashino T

Plant Signal Behav. Vol. 8 ( 2 ) 2012.11

Circadian clock- and PIF4-controlled plant growth: a coincidence mechanism directly integrates a hormone signaling network into the photoperiodic control of plant architectures in Arabidopsis thaliana. Reviewed

Nomoto Y, Kubozono S, Yamashino T, Nakamichi N, Mizuno T

Plant Cell Physiol. Vol. 53 ( 11 ) page： 1950-1964 2012.11

A circadian clock- and PIF4-mediated double coincidence mechanism is implicated in the thermosensitive photoperiodic control of plant architectures in Arabidopsis thaliana. Reviewed

Nomoto Y, Kubozono S, Miyachi M, Yamashino T, Nakamichi N, Mizuno T

Plant Cell Physiol. Vol. 53 ( 11 ) page： 1965-1973 2012.11

Transcriptional repressor PRR5 directly regulates clock-output pathways. Reviewed

Nakamichi N, Kiba T, Kamioka M, Suzuki T, Yamashino T, Higashiyama T, Sakakibara H, Mizuno T

Proc Natl Acad Sci U S A Vol. 109 ( 42 ) page： 17123-17128 2012.10

Characterization of shade avoidance responses in Lotus japonicus. Reviewed

Ueoka-Nakanishi H, Hori N, Ishida K, Ono N, Yamashino T, Nakamichi N, Mizuno T

Biosci Biotechnol Biochem. Vol. 75 ( 11 ) page： 2148-2154 2011.11

Light-responsive double B-box containing transcription factors are conserved in Physcomitrella patens. Reviewed

Yamawaki S, Yamashino T, Nakamichi N, Nakanishi H, Mizuno T

Biosci Biotechnol Biochem. Vol. 75 ( 10 ) page： 2037-2041 2011.10

Functional characterization of HY5 homolog genes involved in early light-signaling in Physcomitrella patens. Reviewed

Yamawaki S, Yamashino T, Nakanishi H, Mizuno T

Biosci Biotechnol Biochem. Vol. 75 ( 8 ) page： 1533-1539 2011.8

Phytochrome-interacting factor 4 and 5 (PIF4 and PIF5) activate the homeobox ATHB2 and auxin-inducible IAA29 genes in the coincidence mechanism underlying photoperiodic control of plant growth of Arabidopsis thaliana. Reviewed

Kunihiro A, Yamashino T, Nakamichi N, Niwa Y, Nakanishi H, Mizuno T

Plant Cell Physiol. Vol. 52 ( 8 ) page： 1315-1329 2011.8

Heterologous expression and functional characterization of a Physcomitrella Pseudo response regulator homolog, PpPRR2, in Arabidopsis. Reviewed

Satbhai SB, Yamashino T, Mizuno T, Aoki S.

Biosci Biotechnol Biochem. Vol. 75 page： 786-789 2011.5

Pseudo-Response Regulator (PRR) Homologues of the Moss Physcomitrella patens: Insights into the Evolution of the PRR Family in Land Plants. Reviewed

Satbhai SB, Yamashino T, Okada R, Nomoto Y, Mizuno T, Tezuka Y, Itoh T, Tomita M, Otsuki S, Aoki S.

DNA Res. Vol. 18 page： 39-52 2011.2

Classification of the genes involved in the two-component system of the moss Physcomitrella patens. Reviewed

Ishida K, Yamashino T, Nakanishi H, Mizuno T.

Biosci Biotechnol Biochem. Vol. 74 page： 2542-2545 2010.12

PHYTOCHROME-INTERACTING FACTORS PIF4 and PIF5 are implicated in the regulation of hypocotyl elongation in response to blue light in Arabidopsis thaliana. Reviewed

Kunihiro A, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 74 page： 2538-2541 2010.12

Genomewide characterization of the light-responsive and clock-controlled output pathways in Lotus japonicus with special emphasis of its uniqueness. Reviewed

Ono N, Ishida K, Yamashino T, Nakanishi H, Sato S, Tabata S, Mizuno T.

Plant Cell Physiol. Vol. 51 page： 1800-1814 2010.10

Biochemical characterization of plant hormone cytokinin-receptor histidine kinases using microorganisms.

Mizuno T, Yamashino T.

Methods Enzymol. Vol. 471 page： 335-356 2010.3

*A genome-wide compilation of the two-component systems in Lotus japonicus. Reviewed

Ishida K, Niwa Y, Yamashino T, Mizuno T

DNA Res. Vol. 16 ( 4 ) page： 237-247 2009.8

The circadian clock regulates the photoperiodic response of hypocotyl elongation through a coincidence mechanism in Arabidopsis thaliana. Reviewed

Niwa Y, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 50 ( 4 ) page： 838-854 2009.4

Transcript profiling of an Arabidopsis PSEUDO RESPONSE REGULATOR arrhythmic triple mutant reveals a role for the circadian clock in cold stress response. Reviewed

Nakamichi N, Kusano M, Fukushima A, Kita M, Ito S, Yamashino T, Saito K, Sakakibara H, Mizuno T

Plant Cell Physiol. Vol. 50 page： 447-462 2009.3

A genetic study of the Arabidopsis circadian clock with reference to the TIMING OF CAB EXPRESSION 1 (TOC1) gene. Reviewed

Ito S, Kawamura H, Niwa Y, Nakamichi N, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 50 page： 290-303 2009.2

*Involvement of Arabidopsis clock-associated pseudo-response regulators in diurnal oscillations of gene expression in the presence of environmental time cues. Reviewed

Yamashino T, Ito S, Niwa Y, Kunihiro A, Nakamichi N, Mizuno T

Plant Cell Physiol. Vol. 49 ( 12 ) page： 1839-1850 2008.12

Expression of the cytokinin-induced type-A response regulator gene ARR9 is regulated by the circadian clock in Arabidopsis thaliana. Reviewed

Ishida K, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 72 page： 3025-3029 2008.11

A small subfamily of Arabidopsis RADIALIS-LIKE SANT/MYB genes: a link to HOOKLESS1-mediated signal transduction during early morphogenesis. Reviewed

Hamaguchi A, Yamashino T, Koizumi N, Kiba T, Kojima M, Sakakibara H, Mizuno T.

Biosci Biotechnol Biochem. Vol. 72 page： 2687-2696 2008.10

Characterization of genetic links between two clock-associated genes, GI and PRR5 in the current clock model of Arabidopsis thaliana. Reviewed

Kawamura H, Ito S, Yamashino T, Niwa Y, Nakamichi N, Mizuno T.

Biosci Biotechnol Biochem. Vol. 72 page： 2770-2774 2008.10

Characterization of bZip-type transcription factor AtfA with reference to stress responses of conidia of Aspergillus nidulans. Reviewed

Hagiwara D, Asano Y, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 72 page： 2756-2760 2008.10

The common function of a novel subfamily of B-Box zinc finger proteins with reference to circadian-associated events in Arabidopsis thaliana. Reviewed

Kumagai T, Ito S, Nakamichi N, Niwa Y, Murakami M, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 72 page： 1539-1549 2008.6

The function of the clock-associated transcriptional regulator CCA1 (CIRCADIAN CLOCK-ASSOCIATED 1) in Arabidopsis thaliana. Reviewed

Kawamura M, Ito S, Nakamichi N, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 72 page： 1307-1316 2008.5

Comparative transcriptome of diurnally oscillating genes and hormone-responsive genes in Arabidopsis thaliana: insight into circadian clock-controlled daily responses to common ambient stresses in plants. Reviewed

Mizuno T, Yamashino T.

Plant Cell Physiol. Vol. 49 page： 481-487 2008.5

Insight into missing genetic links between two evening-expressed pseudo-response regulator genes TOC1 and PRR5 in the circadian clock-controlled circuitry in Arabidopsis thaliana. Reviewed

Ito S, Niwa Y, Nakamichi N, Kawamura H, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 49 page： 201-213 2008.2

*Three type-B response regulators, ARR1, ARR10 and ARR12, play essential but redundant roles in cytokinin signal transduction throughout the life cycle of Arabidopsis thaliana. Reviewed

Ishida K, Yamashino T, Yokoyama A, Mizuno T.

Plant Cell Physiol. Vol. 49 ( 1 ) page： 47-57 2008.1

Language：English Publishing type：Research paper (scientific journal)

Arabidopsis thaliana has 11 members belonging to the typical type-B ARR (authentic response regulator) family. Among them, seven highly homologous members appear also to be conserved in rice (Oryza sativa), but others are not. It was suggested that these seven ARRs are commonly implicated as DNA-binding transcription factors in the phosphorelay-mediated cytokinin signal transduction network in higher plants. To gain an insight into the functions of the cytokinin-associated type-B ARRs, we previously investigated an arr1 arr10 arr12 triple mutant and reported that it exhibited stunted growth and abnormality in vascular development. Based on this fact, here we attempted to characterize the mutant intensively with reference to cytokinin-associated phenotypes through the life cycle. We showed that the observed cytokinin-associated phenotypes of arr1 arr10 arr12 were very severe and highly analogous to those observed for certain ahk2 ahk3 ahk4/cre1 triple mutants, which have virtually no cytokinin receptor to propagate the phosphorelay signal transduction network. Among the seven ARR members belonging to the cytokinin-associated type-B ARR subfamily, it was thus suggested that ARR1, ARR10 and ARR12 together play essential (or general) roles in cytokinin signal transduction. It is therefore conceivable that the other type-B ARRs (ARR2, ARR11, ARR14 and ARR18) might play more specific roles spatially and temporally in plants.

Identification of amino acid substitutions that render the Arabidopsis cytokinin receptor histidine kinase AHK4 constitutively active. Reviewed

Miwa K, Ishikawa K, Terada K, Yamada H, Suzuki T, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 48 page： 1809-1814 2007.12

Rhythmic and light-inducible appearance of clock-associated pseudo-response regulator protein PRR9 through programmed degradation in the dark in Arabidopsis thaliana. Reviewed

Ito S, Nakamichi N, Kiba T, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 48 page： 1644-1651 2007.11

In vitro analysis of His-Asp phosphorelays in Aspergillus nidulans: the first direct biochemical evidence for the existence of His-Asp phosphotransfer systems in filamentous fungi. Reviewed

Azuma N, Kanamaru K, Matsushika A, Yamashino T, Mizuno T, Kato M, Kobayashi T

Biosci Biotechnol Biochem. Vol. 71 page： 2493-2502 2007.10

Characterization of the bZip-type transcription factor NapA with reference to oxidative stress response in Aspergillus nidulans. Reviewed

Asano Y, Hagiwara D, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 7 ) page： 1800-1803 2007.7

Genetic linkages between circadian clock-associated components and phytochrome-dependent red light signal transduction in Arabidopsis thaliana. Reviewed

Ito S, Nakamichi N, Nakamura Y, Niwa Y, Kato T, Murakami M, Kita M, Mizoguchi T, Niinuma K, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 48 ( 7 ) page： 971-983 2007.7

Genetic linkages of the circadian clock-associated genes, TOC1, CCA1 and LHY, in the photoperiodic control of flowering time in Arabidopsis thaliana. Reviewed

Niwa Y, Ito S, Nakamichi N, Mizoguchi T, Niinuma K, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 48 ( 7 ) page： 925-937 2007.7

Characterization of a unique GATA family gene that responds to both light and cytokinin in Arabidopsis thaliana. Reviewed

Naito T, Kiba T, Koizumi N, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 6 ) page： 1557-1560 2007.6

Arabidopsis clock-associated pseudo-response regulators PRR9, PRR7 and PRR5 coordinately and positively regulate flowering time through the canonical CONSTANS-dependent photoperiodic pathway. Reviewed

Nakamichi N, Kita M, Niinuma K, Ito S, Yamashino T, Mizoguchi T, Mizuno T.

Plant Cell Physiol. Vol. 48 ( 6 ) page： 822-832 2007.6

Characterization of a set of phytochrome-interacting factor-like bHLH proteins in Oryza sativa. Reviewed

Nakamura Y, Kato T, Yamashino T, Murakami M, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 5 ) page： 1183-1191 2007.5

A link between cytokinin and ASL9 (ASYMMETRIC LEAVES 2 LIKE 9) that belongs to the AS2/LOB (LATERAL ORGAN BOUNDARIES) family genes in Arabidopsis thaliana. Reviewed

Naito T, Yamashino T, Kiba T, Koizumi N, Kojima M, Sakakibara H, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 5 ) page： 1269-1278 2007.5

The SskA and SrrA response regulators are implicated in oxidative stress responses of hyphae and asexual spores in the phosphorelay signaling network of Aspergillus nidulans. Reviewed

Hagiwara D, Asano Y, Marui J, Furukawa K, Kanamaru K, Kato M, Abe K, Kobayashi T, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 4 ) page： 1003-1014 2007.4

Characterization of the rice circadian clock-associated pseudo-response regulators in Arabidopsis thaliana. Reviewed

Murakami M, Tago Y, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 4 ) page： 1107-1110 2007.4

Mutants of circadian-associated PRR genes display a novel and visible phenotype as to light responses during de-etiolation of Arabidopsis thaliana seedlings. Reviewed

Kato T, Murakami M, Nakamura Y, Ito S, Nakamichi N, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 3 ) page： 834-839 2007.3

Characterization of the NikA histidine kinase implicated in the phosphorelay signal transduction of Aspergillus nidulans, with special reference to fungicide responses. Reviewed

Hagiwara D, Matsubayashi Y, Marui J, Furukawa K, Yamashino T, Kanamaru K, Kato M, Abe K, Kobayashi T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 3 ) page： 844-847 2007.3

Characterization of Circadian-associated pseudo-response regulators: I. Comparative studies on a series of transgenic lines misexpressing five distinctive PRR Genes in Arabidopsis thaliana. Reviewed

Matsushika A, Murakami M, Ito S, Nakamichi N, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 2 ) page： 527-534 2007.2

*AHK5 histidine kinase regulates root elongation through an ETR1-dependent abscisic acid and ethylene signaling pathway in Arabidopsis thaliana. Reviewed

Iwama A, Yamashino T, Tanaka Y, Sakakibara H, Kakimoto T, Sato S, Kato T, Tabata S, Nagatani A, Mizuno T.

Plant Cell Physiol. Vol. 48 ( 2 ) page： 375-380 2007.2

Characterization of circadian-associated pseudo-response regulators: II. The function of PRR5 and its molecular dissection in Arabidopsis thaliana. Reviewed

Matsushika A, Kawamura M, Nakamura Y, Kato T, Murakami M, Yamashino T, Mizuno T.

Biosci Biotechnol Biochem. Vol. 71 ( 2 ) page： 535-544 2007.2

Type-B ARR transcription factors, ARR10 and ARR12, are implicated in cytokinin-mediated regulation of protoxylem differentiation in roots of Arabidopsis thaliana. Reviewed

Yokoyama A, Yamashino T, Amano Y, Tajima Y, Imamura A, Sakakibara H, Mizuno T.

Plant Cell Physiol. Vol. 48 ( 1 ) page： 84-96 2007.1

Comparative overviews of clock-associated genes of Arabidopsis thaliana and Oryza sativa. Reviewed

Murakami M, Tago Y, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 48 ( 1 ) page： 110-121 2007.1

PSEUDO-RESPONSE REGULATORS, PRR9, PRR7 and PRR5, together play essential roles close to the circadian clock of Arabidopsis thaliana. Reviewed

Nakamichi N, Kita M, Ito S, Yamashino T, Mizuno T.

Vol. 46 ( 5 ) page： 686-698 2005.5

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, a number of clock-associated protein components have been identified. Among them, CCA1 (CIRCADIAN CLOCK-ASSOCIATED 1)/LHY (LATE ELONGATED HYPOCOTYL) and TOC1 (TIMING OF CAB EXPRESSION 1) are believed to be the essential components of the central oscillator. CCA1 and LHY are homologous and partially redundant Myb-related DNA-binding proteins, whereas TOC1 is a member of a small family of proteins, designated as PSEUDO-RESPONSE REGULATOR. It is also believed that these two different types of clock components form an autoregulatory positive/negative feedback loop at the levels of transcription/translation that generates intrinsic rhythms. Nonetheless, it was not yet certain whether or not other PRR family members (PRR9, PRR7, PRR5 and PRR3) are implicated in clock function per se. Employing a set of prr9, prr7 and prr5 mutant alleles, here we established all possible single, double and triple prr mutants. They were examined extensively by comparing them with each other with regard to their phenotypes of circadian rhythms, photoperiodicity-dependent control of flowering time and photomorphogenic responses to red light during de-etiolation. Notably, the prr9 prr7 prr5 triple lesions in plants resulted in severe phenotypes: (i) arrhythmia in the continuous light conditions, and an anomalous phasing of diurnal oscillation of certain circadian-controlled genes even in the entrained light/dark cycle conditions; (ii) late flowering that was no longer sensitive to the photoperiodicity; and (iii) hyposensitivity (or blind) to red light in the photomorphogenic responses. The phenotypes of the single and double mutants were also characterized extensively, showing that they exhibited circadian-associated phenotypes characteristic for each. These results are discussed from the viewpoint that PRR9/PRR7/PRR5 together act as period-controlling factors, and they play overlapping and distinctive roles close to (or within) the central oscillator in which the rela

PRR5 (PSEUDO-RESPONSE REGULATOR 5) plays antagonistic roles to CCA1 (CIRCADIAN CLOCK-ASSOCIATED 1) in Arabidopsis thaliana Reviewed

Fujimori T, Sato E, Yamashino T, Mizuno T

Biosci. Biotechnol. Biochem. Vol. 69 ( 2 ) page： 426-430 2005.2

Language：English Publishing type：Research paper (scientific journal)

In general, the clock (or oscillator) is central to circadian rhythms in many organisms. In the model higher plant Arabidopsis thaliana, the best candidates for clock components are CCA1 (CIRCADIAN CLOCK-ASSOCIATED 1) and LHY (LATE ELONGATED HYPOCOTYL), which are homologous Myb-related transcription factors. It is also believed that TOC1 (TIMING OF CAB EXPRESSION 1) is another component of the central oscillator. In this connection, we have been characterizing a small family of proteins, designated ARABIDOPSIS PSEUDO-RESPONSE REGULATOR (PRR1, PRR3, PRR5, PRR7, and PRR9), based on the fact that one of the members (PRR1) is identical to TOC1. Nevertheless, it is not yet certain whether other PRR family members are also implicated in clock function per se. To address this issue, in this study we examined a functional interaction between the CCA1 clock component and one of the PRR family members, PRR5, by employing transgenic lines overexpressing both the CCA1 and PRR5 genes. Evidence will be provided that PRR5 plays an antagonistic role(s) to the putative CCA1 clock component.

The Arabidopsis pseudo-response regulators, PRR5 and PRR7, coordinately play essential roles for circadian clock function Reviewed

Nakamichi N, Kita M, Ito S, Sato E, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 46 ( 4 ) page： 609-619 2005.2

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, a number of clock-associated protein factors have been identified. Among them, TOC1 (TIMING OF CAB EXPRESSION 1) is believed to be a component of the central oscillator. TOC1 is a member of a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATOR, including PRR1/TOC1, PRR3, PRR5, PRR7 and PRR9. It has not been certain whether or not other PRR family members are also implicated in clock function per se. To clarify this problem, here we constructed a double mutant line, which is assumed to have severe lesions in both the PRR5 and PRR7 genes. Resulting homozygous prr5-11 prr7-11 young seedlings showed a marked phenotype of hyposensitivity to red light during de-etiolation. In addition, they displayed a phenotype of extremely late flowering under long-day photoperiod conditions, but not short-day conditions. The rhythms at the level of transcription of certain clock-controlled genes were severely perturbed in the double mutant plants when they were released into continuous light (LL) and darkness (DD). The observed phenotype was best interpreted as 'arrhythmic in both LL and DD' and/or 'very short period with markedly reduced amplitude'. Even under the light entrainment (LD) conditions, the mutant plants showed anomalous diurnal oscillation profiles with altered amplitude and/or phase with regard to certain clock-controlled genes, including the clock component CCA1 (CIRCADIAN CLOCK-ASSOCIATED 1) gene. Such events were observed even under temperature entrainment conditions, suggesting that the prr5-11 prr7-11 lesions cannot simply be attributed to a defect in the light signal input pathway. These pleiotropic circadian-associated phenotypes of the double mutant were very remarkable, as compared with those observed previously for each single mutant. Taking these results together, we propose for the first time that PRR5 and PRR7 coordinately (or synergistically) play essential clock-associated roles close to the central oscill

Combinatorial microarray analysis revealing Arabidopsis genes implicated in cytokinin responses through the His->Asp Phosphorelay circuitry Reviewed

Kiba T, Naitou T, Koizumi N, Yamashino T, Sakakibara H, Mizuno T

Plant Cell Physiol. Vol. 46 ( 2 ) page： 339-355 2005.2

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, the immediate early response of plants to cytokinin is formulated as the multistep histidine kinase (AHK)-->histidine-containing phosphotransmitter (AHP)-->response regulator (ARR) phosphorelay signaling circuitry, which is initiated by the cytokinin receptor histidine protein kinases. In the hope of finding components (or genes) that function downstream of the cytokinin-mediated His-->Asp phosphorelay signaling circuitry, we carried out genome-wide microarray analyses. To this end, we used a combinatorial microarray strategy by employing not only wild-type plants, but also certain transgenic lines in which the cytokinin-mediated His-->Asp phosphorelay signaling circuitry has been genetically manipulated. These transgenic lines employed were ARR21-overexpressing and ARR22-overexpressing plants, each of which exhibits a characteristic phenotype with regard to the cytokinin-mediated His-->Asp phosphorelay. The results of extensive microarray analyses with these plants allowed us systematically to identify a certain number of genes that were up-regulated at the level of transcription in response to cytokinin directly or indirectly. Among them, some representatives were examined further in wild-type plants to support the idea that certain genes encoding transcription factors are rapidly and specifically induced at the level of transcription by cytokinin in a manner similar to that of the type-A ARR genes, which are the hallmarks of the His-->Asp phosphorelay signaling circuitry. Several interesting transcription factors were thus identified as being cytokinin responsive, including those belonging to the AP2/EREBP family, MYB family, GATA family or bHLH family. Including these, the presented list of cytokinin-up-regulated genes (214) will provide us with valuable bases for understanding the His-->Asp phosphorelay in A. thaliana.

Molecular dissection of the promoter of the light-induced and circadian-controlled APRR9 gene encoding a clock-associated component of Arabidopsis thaliana. Reviewed

Ito S, Nakamichi N, Matsushika A, Fujimori T, Yamashino T, Mizuno T.

Biosci. Biotechnol. Biochem. Vol. 69 ( 2 ) page： 382-390 2005.2

Language：English Publishing type：Research paper (scientific journal)

In the model higher plant Arabidopsis thaliana, a number of circadian clock-associated protein components have recently been identified. Among them, a small family of ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9) is interesting because the most probable clock component TIMING OF CAB EXPRESSION 1 (TOC1) belongs to this family. Several lines of evidence have already been accumulated to support the view that not only APRR1/TOC1 but also other APRR family members are crucial for a better understanding of the molecular link between circadian rhythm and light-signal transduction. Among the APRR1/TOC1 family members, the circadian-controlled APRR9 gene is unique in that its expression is rapidly induced by light at the level of transcription. In this study we dissected the regulatory cis-elements of the light-induced and/or circadian-controlled APRR9 promoter by employing not only a mutant plant carrying a T-DNA insertion in the APRR9 promoter, but also a series of APRR9-promoter::LUC (luciferase) reporters that were introduced into an Arabidopsis cultured cell line (T87 cells). Taking the results of these approaches together, we provide several lines of evidence that the APRR9 promoter contains at least two distinctive and separable regulatory cis-elements: an "L element" responsible for the light-induced expression, followed by an "R element" necessary for the fundamental rhythmic expression of APRR9. Furthermore, APRR1/TOC1 was implicated in the L-element-mediated light response of APRR9, directly or indirectly.

Circadian-associated rice pseudo response regulators (OsPRRs): insight into the control of flowering time. Reviewed

Murakami M, Matsushika A, Ashikari M, Yamashino T, Mizuno T

Biosci. Biotechnol. Biochem. Vol. 69 ( 2 ) page： 410-414 2005.2

Language：English Publishing type：Research paper (scientific journal)

A small family of plant proteins, designated PSEUDO RESPONSE REGULATORS (PRRs), is crucial for a better understanding of the molecular link between circadian rhythm and photoperiodic control of flowering time in the dicotyledonous model plant Arabidopsis thaliana. Recently, we showed that the monocotyledonous model plant Oryza sativa also has homologous members of the OsPRR family (Oryza sativa PRR). In the previous experiments with rice, we mainly characterized a japonica variety (Nipponbare). By employing an indica variety (Kasalath), in this study we further characterized OsPRRs with reference to the photoperiod sensitivity Hd (Heading date) QTL (quantitative trait loci) implicated in the control of flowering time in rice. The circadian-controlled and sequential expression profiles of the five OsPRR genes were observed not only for Nipponbare but also for Kasalath. Then each of these OsPRR genes was mapped on the rice chromosomes. Among these OsPRR genes, OsPRR37 was mapped very closely to Hd2-QTL, which was identified as the major locus that enhances the photoperiod sensitivity of flowering in Nipponbare. Furthermore, we found that Kasalath has a severe mutational lesion in the OsPRR37 coding sequence.

Molecular basis for promoter selectivity of the transcriptional activator OmpR of Escherichia coli: isolation of mutants that can activate the non-cognate kdpABC promoter. Reviewed

Ohashi K, Yamashino T, Mizuno T

J. Biochem. (Tokyo) Vol. 137 ( 1 ) page： 51-59 2005.1

Language：English Publishing type：Research paper (scientific journal)

Escherichia coli has two osmo-responsive two-component regulatory systems, the EnvZ-OmpR and KdpD-KdpE systems, each of which consists of a sensor histidine protein kinase and a response regulator. The OmpR and KdpE response regulators belong to the same family of DNA-binding proteins, and act as positive transcriptional factors in response to the medium osmolarity. However, OmpR specifically activates the ompC gene encoding the OmpC outer membrane protein, whereas KdpE exclusively activates the kdpABC operon encoding the high-affinity Kdp potassium-transporter. To gain insight into the molecular basis for such strict promoter selectivity, we isolated OmpR mutants that can activate the non-cognate kdpABC promoter in vivo. For these OmpR mutants, it was found that a few common and crucial amino acids are responsible for the altered property of OmpR (e.g., Gly-164, Glu-193). In vitro properties of these OmpR mutants were further examined by means of DNA-binding assays and DNA-footprinting analyses with reference to the kdpABC promoter. These results were interpreted on the basis of the three-dimensional structure of the C-terminal half of OmpR, which consists of a DNA-binding helix-turn-helix motif and a RNA polymerase-interacting surface. The results of this study were best explained by assuming that the isolated OmpR mutants have an altered property with regard to the interaction with RNA polymerase on the kdpABC promoter. We propose that the promoter selectivity of OmpR is determined not only by its DNA-binding specificity, but also by the spatial configuration of the promoter on which OmpR must properly associate with RNA polymerase.

Rapid response of Arabidopsis T87 cultured cells to cytokinin through His-to-Asp phosphorelay signal transduction Reviewed

Yamada H, Koizumi N, Nakamichi N, Kiba T, Yamashino T, Mizuno T.

Biosci. Biotechnol. Biochem. Vol. 68 ( 9 ) page： 1966-1976 2004.9

Circadian-controlled basic/helix-loop-helix factor, PIL6, implicated in light-signal transduction in Arabidopsis thaliana Reviewed

Fujimori T, Yamashino T, Kato T, Mizuno T

Plant Cell Physiol. Vol. 45 ( 8 ) page： 1078-1086 2004.8

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

PHYTOCHROME-INTERACTING FACTOR-LIKE 6 (PIL6) is a member of the large family of basic/helix-loop-helix (bHLH) factors in Arabidopsis thaliana. This circadian-controlled transcription factor was previously suggested to interact with the clock component, TIMING OF CAB EXPRESSION 1 (TOC1). In this study, we isolated a loss-of-function mutant of PIL6, together with a transgenic line aberrantly expressing PIL6 in a manner independent of circadian rhythm. These mutant plants were simultaneously examined with special reference to circadian rhythm and light-signal transduction. The results suggested that PIL6 appears to be not directly involved in the clock function per se. However, the loss-of-function mutant (pil6-1) showed a remarkable phenotype in that it is hypersensitive to red light in seedling de-etiolation. This phenotype was similar to that observed for transgenic lines overexpressing TOC1 (or APRR1). Conversely, transgenic plants overexpressing PIL6 (PIL6-ox) are hyposensitive to red light under the same conditions. This phenotype was very similar to that observed for phyB mutants. The developmental morphologies of PIL6-ox, including the phenotype of early flowering, were also similar to those of phyB mutants. We propose that PIL6 acts as a negative regulator for a red light-mediated morphogenic response (e.g., elongation of hypocotyls in de-etiolation). Taken together, PIL6 might function at an interface between the circadian clock and red light-signal transduction pathways.

A Genome-wide view of the Escherichia coli BasS-BasR two-component system implicated in iron-responses Reviewed

Hagiwara D, Yamashino T, Mizuno T

Biosci. Biotechnol. Biochem. Vol. 68 ( 8 ) page： 1758-1767 2004.8

Language：English Publishing type：Research paper (scientific journal)

Histidine-to-aspartate (His-->Asp) phosphorelay (or two-component) systems are very common signal transduction mechanisms that are implicated in a wide variety of cellular responses to environmental stimuli in both prokaryotes and eukaryotes. Determination of the entire genomic sequence of Escherichia coli revealed that this gram-negative bacterium has 29 His-kinases and 32 response regulators. Of the 29 His-kinases, 23 have already been experimentally characterized at least to some extent in terms of their physiological functions. No physiological stimulus has yet been identified for each of the remaining 6 His-kinases (BasS, CreC, RstB, YfhK, YehU, and YpdA). Here we characterized the BasS-BasR two-component system with reference to its physiological function, taking genetic approaches together with genome-wide transcriptome profiling. First we showed that the hypothetical yfbE operon that appears to be implicated in the modification of lipopolysaccharides is regulated at the level of transcription in response to external iron, and then we showed that the BasS-BasR system is essential for this iron-dependent induction of yfbE. Another PhoQ-PhoP two-component system was also implicated in the full induction of yfbE in response to iron, but it was not essential. To gain more insight into the BasS-BasR system, we conducted genome-wide transcriptome analysis by microarray, finding that many of the uncovered putative iron-induced and BasS-BasR-dependent genes are somehow associated with acidic and/or anaerobic growth conditions. In this respect, it was found that mutant cells defective in the BasS-BasR system were sensitive to mild-acid growth conditions in the presence of a relatively high concentration of iron. These results are discussed with regard to a comprehensive picture of the His-->Asp phosphorelay signaling network in E. coli.

Characterization of circadian-associated APRR3 pseudo-response regulator belonging to the APRR1/TOC1 quintet in Arabidopsis thaliana Reviewed

Murakami M, Yamashino T, Mizuno T

Vol. 45 ( 5 ) page： 645-650 2004.5

Language：English Publishing type：Research paper (scientific journal)

In higher plants, there are wide ranges of biological processes that are controlled through the circadian clock. In this connection, we have been characterizing a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1, APRR3, APRR5, APRR7, and APRR9), among which APRR1 is identical to TOC1 (TIMING OF CAB EXPRESSION1) that is believed to be a component of the central oscillator. Through previous genetic studies, several lines of evidence have already been provided to support the view that, not only APRR1/TOC1, but also other APRR1/TOC1 quintet members are important for a better understanding of the molecular links between circadian rhythm, control of flowering time, and also photomorphogenesis. However, the least characterized one was APRR3 in that no genetic study has been conducted to see if APRR3 also plays an important role in the circadian-associated biological events. Here we show that APRR3-overexpressing transgenic plants (APRR3-ox) exhibited: (i). a phenotype of longer period (and/or delayed phase) of rhythms of certain circadian-controlled genes under continuous white light, (ii). a phenotype of late flowering under long-day photoperiod conditions, (iii). a phenotype of hypo-sensitiveness to red light during early photomorphogenesis of de-etiolated seedlings, supporting the current idea as to the APRR1/TOC1 quintet described above.

Genome-wide comparison of the His-to-Asp phosphorelay signaling components of three symbiotic genera of Rhizobia Reviewed

Hagiwara D, Yamashino T, Mizuno T

DNA Res. Vol. 11 ( 1 ) page： 57-65 2004.2

Language：English Publishing type：Research paper (scientific journal)

Histidine-to-aspartate (His-Asp) phosphorelay (or two-component) systems are very common signal transduction mechanisms that are implicated in a wide variety of cellular responses to environmental stimuli. The His-Asp phosphorelay components include "sensor histidine kinase (HK)", "phosphotransfer intermediate (HPt)", and "response regulator (RR)". With special reference to three bacterial species (Mesorhizobium loti, Bradyrhizobium japonicum, Sinorhizobium meliloti), each of which belongs to a different genera of Rhizobia, here we attempted to compile all of the His-Asp phosphorelay components in order to reveal a comparative genome-wide overview as to the His-Asp phosphorelay. It was revealed that M. loti has 47 HKs, 1 HPts, and 58 RRs; B. japonicum has 80 HKs, 3 HPts, and 91 RRs; whereas S. meliloti has 40 HKs, 1 HPt, and 58 RRs. These His-Asp phosphorelay components were extensively compiled and characterized. The resulting overview as to the His-Asp phosphorelay of Rhizobia will provide us with a basis for understanding of the fundamental mechanisms underlying interactions between plants and microorganisms (including symbiosis), as well as nitrogen fixation.

Comparative studies of the AHP histidine-containing phosphotransmitters implicated in His-to-Asp phosphorelay in Arabidopsis thaliana Reviewed

Tanaka Y, Suzuki T, Yamashino T, Mizuno T

Biosci. Biotechnol. Biochem. Vol. 68 ( 2 ) page： 462-465 2004.2

Language：English Publishing type：Research paper (scientific journal)

The evolutionarily-conserved histidine to aspartate (His-to-Asp) phosphorelay signal transduction is common in both prokaryotes and eukaryotes. Such a phosphorelay system is generally made up of 'a histidine (His)-kinase', 'a histidine-containing phosphotransmitter (HPt)', and 'a phospho-accepting response regulator (RR)'. In general, an HPt factor acts as an intermediate in a given multistep His-to-Asp phosphorelay. In Arabidopsis thaliana, this model higher plant has five genes (named AHP1 to AHP5), each of which seems to encode an HPt factor. Recent studies suggested that the His-to-Asp phosphorelay involving the AHP factors is at least partly implicated in signal transduction in response to cytokinin (a plant hormone). Nevertheless, the properties of AHPs have not yet been fully clarified. Here we did comparative studies of all the AHP factors, in terms of (i) expression profiles in plants, (ii) intracellular localization, (iii) ability to acquire a phosphoryl group in vitro, and (iv) ability to interact with the downstream components, ARRs (Arabidopsis response regulators). The results of this study provided us with a comprehensive view at the molecular level for understanding the functions of the AHP phosphotransmitters in the His-to-Asp phosphorelay.

Characterization of plant circadian rhythms by employing Arabidopsis</> cultured cells with bioluminescence reporters Reviewed

Nakamichi N, Ito S, Oyama T, Yamashino T, Kondo T, Mizuno T

Plant Cell Physiol. Vol. 45 ( 1 ) page： 57-67 2004.1

Language：English Publishing type：Research paper (scientific journal)

Recent intensive studies have begun to shed light on the molecular mechanisms underlying the plant circadian clock in Arabidopsis thaliana. During the course of these previous studies, the most powerful technique, elegantly adopted, was a real-time bioluminescence monitoring system of circadian rhythms in intact plants carrying a luciferase (LUC) fusion transgene. We previously demonstrated that Arabidopsis cultured cells also retain an ability to generate circadian rhythms, at least partly. To further improve the cultured cell system for studies on circadian rhythms, here we adopted a bioluminescence monitoring system by establishing the cell lines carrying appropriate reporter genes, namely, CCA1::LUC and APRR1::LUC, with which CCA1 (CIRCADIAN CLOCK-ASSOCIATED1) and APRR1 (or TOC1) (ARABIDOPSIS PSEUDO-RESPONSE REGULATORS1 or TIMING OF CAB EXPRESSION1) are believed to be the components of the central oscillator. We report the results that consistently supported the view that the established cell lines, equipped with such bioluminescence reporters, might provide us with an advantageous means to characterize the plant circadian clock.

Comparative studies on the type-B response regulators revealing their distinctive properties in the His-to-Asp phosphorelay signal transduction of Arabidopsis thaliana Reviewed

Tajima Y, Imamura A, Kiba T, Amano Y, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 45 ( 1 ) page： 28-39 2004.1

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, a Histidine-to-Aspartate (His-->Asp) phosphorelay is involved in the signal transduction for propagation of certain stimuli, such as plant hormones. Through the phosphorelay, the type-B phospho-accepting response regulator (ARR) family members serve as DNA-binding transcriptional regulators, whose activities are most likely regulated by phosphorylation/dephosphorylation. Based on the fact that this higher plant has 11 type-B ARR family genes, we clarified the expression profiles for all of their transcripts in plants. We constructed and characterized a series of transgenic lines, each carrying a given ARR-promoter::GUS transgene. Transcripts of some type-B ARR family genes were detected more or less ubiquitously in many organs tested, while others were expressed predominantly in reproductive organs. These ARR family members were phylogenetically classified into three sub-families, the largest of which includes the well-characterized ARR1, ARR2, and ARR11. Comparative studies were conducted focusing on ARR20 and ARR21, each of which is a representative member of an uncharacterized minor sub-family. A set of transgenic lines was constructed, in each of which a C-terminal DNA-binding domain lacking the N-terminal phospho-accepting receiver of a given ARR was aberrantly overexpressed. These resulting transgenic lines, including ARR14-C-ox, ARR20-C-ox, and ARR21-C-ox, showed characteristic anomalies during development. These results are discussed with special reference to the His-->Asp phosphorelay signal transduction in A. thaliana.

Characterization of the APRR9 pseudo-response regulator belonging to the APRR1/TOC1 quintet in Arabidopsis thaliana Reviewed

Ito S, Matsushika A, Yamada H, Sato S, Kato T, Tabata S, Yamashino T, Mizuno T.

Plant Cell Physiol. Vol. 44 ( 11 ) page： 1237-1245 2003.11

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, a number of circadian-associated factors have been identified, including TOC1 (TIMING OF CAB EXPRESSION1) that is believed to be a component of the central oscillator. TOC1 is a member of a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9). As demonstrated previously, these APRR1/TOC1 quintet members are crucial for a better understanding of the molecular links between circadian rhythms and photosensory signal transduction. Here we focused on the light-induced quintet member, APRR9, and three critical issues with regard to this member were simultaneously addressed: (i) clarification of the mechanism underlying the light-dependent acute response of APRR9, (ii) clarification of the phenotype of a null mutant of APRR9, (iii) identification of protein(s) that interacts with APRR9. In this study, we present the results that support the following views. (i) A phytochrome-mediated signaling pathway(s) activates the transcription of APRR9, leading to the acute light response of APRR9. (ii) The severe mutational lesion of APRR9 singly, if not directly, affects the period (and/or phase) of free-running rhythms, in continuous light, of every circadian-controlled gene tested, including the clock genes, APRR1/TOC1, CCA1, and LHY. (iii) The APRR9 protein is capable of interacting with APRR1/TOC1, suggesting a hetrodimer formation between these cognate family members. These results are discussed within the context of a current consistent model of the Arabidopsis circadian oscillator.

Comparative genetic studies on the APRR5 and APRR7 genes belonging to the APRR1/TOC1 quintet implicated in circadian rhythm, control of flowering time, and early photomorphogenesis Reviewed

Yamamoto Y, Sato E, Shimizu T, Nakamich N, Sato S, Kato T, Tabata S, Nagatani A, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 44 ( 11 ) page： 1119-1130 2003.11

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, a number of circadian-associated factors have been identified. Among those, TOC1 (TIMING OF CAB EXPRESSION 1) is believed to be a component of the central oscillator. TOC1 is a member of a small family of proteins, designated as Arabidopsis PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9). Nonetheless, it is not very clear whether or not the APRR family members other than APRR1/TOC1 are also implicated in the mechanisms underlying the circadian rhythm. To address this issue further, here we characterized a set of T-DNA insertion mutants, each of which is assumed to have a severe lesion in each one of the quintet genes (i.e. APRR5 and APRR7). For each of these mutants (aprr5-11 and aprr7-11) we demonstrate that a given mutation singly, if not directly, affects the circadian-associated biological events simultaneously: (i) flowering time in the long-day photoperiod conditions, (ii) red light sensitivity of seedlings during the early photomorphogenesis, and (iii) the period of free-running rhythms of certain clock-controlled genes including CCA1 and APRR1/TOC1 in constant white light. These results suggest that, although the quintet members other than APRR1/TOC1 may not be directly integrated into the framework of the central oscillator, they are crucial for a better understanding of the molecular mechanisms underlying the Arabidopsis circadian clock.

The evolutionarily conserved OsPRR quintet: rice pseudo-response regulators implicated in circadian rhythm Reviewed

Murakami M, Ashikari M, Miura K, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 44 ( 11 ) page： 1229-1236 2003.11

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, a number of circadian-associated factors have been identified, including TOC1 (TIMING OF CAB EXPRESSION 1) that is believed to be a component of the central oscillator. TOC1 is a member of a small family of proteins, designated as ARABIDOPSIS PSEUDO-RESPONSE REGULATORS (APRR1/TOC1, APRR3, APRR5, APRR7, and APRR9). As demonstrated previously, these APRR1/TOC1 quintet members are crucial for a better understanding of the molecular links between circadian rhythms, control of flowering time through photoperiodic pathways, and also photosensory signal transduction in this dicotyledonous plant. In this respect, both the dicotyledonous (e.g. A. thaliana) and monocotyledonous (e.g. Oryza sativa) plants might share the evolutionarily conserved molecular mechanism underlying the circadian rhythm. Based on such an assumption, and as the main objective of this study, we asked the question of whether rice also has a set of pseudo-response regulators, and if so, whether or not they are associated with the circadian rhythm. Here we showed that rice has five members of the OsPRR family (Oryza sativa Pseudo-Response Regulator), and also that the expressions of these OsPRR genes are under the control of circadian rhythm. They are expressed in a diurnal and sequential manner in the order of OsPRR73 (OsPRR37)-->OsPRR95 (OsPRR59)-->OsPRR1, which is reminiscent of the circadian waves of the APRR1/TOC1 quintet in A. thaliana. These and other results of this study suggested that the OsPRR quintet, including the ortholog of APRR1/TOC1, might play important roles within, or close to, the circadian clock of rice.

Genome-wide analyses revealing a signaling network of the RcsC-YojN-RcsB phosphorelay system in Escherichia coli Reviewed

Hagiwara D, Sugiura M, Oshima T, Mori H, Aiba H, Yamashino T, Mizuno T

J. Bacteriol. Vol. 185 ( 19 ) page： 5735-5746 2003.10

Language：English Publishing type：Research paper (scientific journal)

In Escherichia coli, capsular colanic acid polysaccharide synthesis is regulated through the multistep RcsC-->YojN-->RcsB phosphorelay. By monitoring a hallmarked cps::lacZ reporter gene, we first searched for physiological stimuli that propagate the Rcs signaling system. The expression of cps::lacZ was activated when cells were grown at a low temperature (20 degrees C) in the presence of glucose as a carbon source and in the presence of a relatively high concentration of external zinc (1 mM ZnCl(2)). In this Rcs signaling system, the rcsF gene product (a putative outer membrane-located lipoprotein) was also an essential signaling component. Based on the defined signaling pathway and physiological stimuli for the Rcs signaling system, we conducted genome-wide analyses with microarrays to clarify the Rcs transcriptome (i.e., Rcs regulon). Thirty-two genes were identified as putative Rcs regulon members; these genes included 15 new genes in addition to 17 of the previously described cps genes. Using a set of 37 two-component system mutants, we performed alternative genome-wide analyses. The results showed that the propagation of the zinc-responsive Rcs signaling system was largely dependent on another two-component system, PhoQ/P. Considering the fact that the PhoQ/P signaling system responds to external magnesium, we obtained evidence which supports the view that there is a signaling network that connects the Rcs system with the PhoQ/P system, which coordinately regulates extracellular polysaccharide synthesis in response to the external concentrations of divalent cations.

The type-A response regulator, ARR15, acts as a negative regulator in the cytokinin-mediated signal transduction in Arabidopsis thaliana Reviewed

Kiba T, Yamada H, Sato S, Kato T, Tabata S, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 44 ( 8 ) page： 868-874 2003.8

Language：English Publishing type：Research paper (scientific journal)

The Arabidopsis thaliana AHK4 histidine kinase (also known as CRE1 or WOL) acts as a cytokinin signal transducer, presumably, in concert with downstream components, such as histidine-containing phosphotransfer factors (AHPs) and response regulators (ARRs), through the histidine-to-aspartate (His-->Asp) phosphorelay. Among 10 members of the type-A ARR family, the cytokinin-induced expression of ARR15 in roots is selectively impaired in the cre1-1 mutant, which carries a mutation in the AHK4 gene, suggesting a link between this type-A response regulator and the AHK4-mediated cytokinin signal transduction in roots. To address this issue further, we characterized a T-DNA insertion mutant of ARR15, and also constructed transgenic lines (referred to as ARR15-ox) that overexpress the ARR15 gene in a manner independent of cytokinin. While the T-DNA insertion mutant (arr15-1) showed no apparent phenotype, the cytokinin-independent overexpression of ARR15 in ARR15-ox plants resulted in a reduced sensitivity toward exogenously applied cytokinin, not only in elongation of roots in plants, but also in green callus formation (or shoot formation) in explants. Cytokinin-induced expressions of certain type-A ARRs were also down-regulated in ARR15-ox plants. These results support the view that ARR15 acts as a repressor that mediates a negative feedback loop in the cytokinin and AHK4-mediated His-->Asp phosphorelay.

A Link between circadian-controlled bHLH factors and the APRR1/TOC1 quintet in Arabidopsis thaliana Reviewed

Yamashino T, Matsushika A, Fujimori T, Sato S, Kato T, Tabata S, Mizuno T

Plant Cell Physiol. Vol. 44 ( 6 ) page： 619-629 2003.6

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

APRR1 (ARABIDPSIS PSUEDO-RESPONSE REGULATOR 1) (or TOC1, TIMING OF CAB EXPRESSION 1) is believed to be a crucial component of biological clocks of Arabidopsis thaliana. Nevertheless, its molecular function remains to be fully elucidated. Based on the results of yeast two-hybrid and in vitro binding assays, we previously showed that APRR1/TOC1 interacts with certain bHLH factors (i.e. PIF3 and PIL1, which are PHYTOCHROME INTERACTING FACTOR 3 and its homolog (PIF3-LIKE 1), respectively). To critically examine the relevance of PIL1 with reference to the function of APRR1/TOC1, T-DNA insertion mutants were isolated for PIL1. No phenotype was observed for such homozygous pil1 mutants, in terms of circadian-associated events in plants. We then examined more extensively a certain set of bHLH factors, which are considerably similar to PIL1 in their structural designs. The results of extensive analyses of such bHLH factors (namely, HFR1, PIL2, PIF4, PIL5 and PIL6) in wild-type and APRR1-overexressing (APRR1-ox) transgenic lines provided us with several new insights into a link between APRR1/TOC1 and these bHLH factors. In yeast two-hybrid assays, APRR1/TOC1 showed the ability to interact with these proteins (except for HFR1), as well as PIL1 and PIF3. Among them, it was found that the expressions of PIF4 and PIL6 were regulated in a circadian-dependent manner, exhibiting free-running robust rhythms. The expressions of PIF4 and PIL6 were regulated also by light in a manner that their transcripts were rapidly accumulated upon exposure of etiolated seedlings to light. The light-induced expressions of PIF4 and PIL6 were severely impaired in APRR1-ox transgenic lines. Taken together, here we propose the novel view that these bHLH factors (PIF4 and PIL6) might play roles, in concert with APRR1/TOC1, in the integration of light-signals to control both circadian and photomorphogenic processes.

Cell autonomous circadian waves of the APRR1/TOC1 quintet in an established cell line of Arabidopsis thaliana Reviewed

Nakamichi N, Matsushika A, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 44 ( 3 ) page： 360-365 2003.3

Language：English Publishing type：Research paper (scientific journal)

A small family of genes, named Arabidopsis Pseudo Response Regulator (APRR), are intriguing with special reference to circadian rhythms in plants, based on the fact that one of the members (APRR1) is identical to TOC1 (Timing of CAB Expression 1) that is believed to encode a clock component. In Arabidopsis plants, each transcript of the APRR1/TOC1 quintet genes starts accumulating after dawn rhythmically and one after another at intervals in the order of APRR9 --> APRR7 --> APRR5 --> APRR3 --> APRR1/TOC1. To characterize such intriguing circadian-associated events, we employed an established Arabidopsis cell line (named T87). When T87 cells were grown in an appropriate light and dark cycle, cell autonomous diurnal oscillations of the APRR1/TOC1 quintet genes were observed at the level of transcription, as seen in intact plants. After transfer to the conditions without any environmental time cues, particularly in constant dark, we further showed that free-running circadian rhythms persisted in the cultured cells, not only for the APRR1/TOC1 quintet genes, but also other typical circadian-controlled genes including CCA1 (Circadian Clock Associated 1), LHY (Late Elongated Hypocotyl) and CCR2 (Cold Circadian Rhythm RNA Binding 2). To our knowledge, this is the first indication of cell autonomous circadian rhythms in cultured cells in Arabidopsis thaliana, which will provide us with an alternative and advantageous means to characterize the plant biological clock.

In vivo and in vitro characterization of the ARR11 response regulator implicated in the His-to-Asp phosphorelay signal transduction in Arabidopsis thaliana Reviewed

Imamura A, Kiba T, Tajima Y, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 44 ( 2 ) page： 122-131 2003.2

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, Histidine-to-Aspartate (His--> Asp) phosphorelay is a paradigm of a signaling system that is considered to be involved in response to plant hormones, including ethylene and cytokinin. In the current framework of His-->Asp phosphorelay in this higher plant, the type-B ARR (response regulator) family members appear to act as DNA-binding transcriptional regulators. Although Arabidopsis thaliana has 11 type-B ARR family members, except for ARR1 and ARR2, no biological information is available with regard to others. As the main objective of this study, we characterized another example, ARR11, in terms of not only its in vitro biochemical properties, but also its biological activity in plants. In plants, the ARR11 gene was expressed predominantly in roots. In vitro, ARR11 showed the ability to acquire a phosphoryl group from a histidine-containing phosphotransfer intermediate (AHP), and also it showed the ability to recognize a specific nucleotide sequence, GGATT. These in vitro results supported the view that ARR11 is indeed a DNA-binding transcription factor, the ability of which is most likely modulated by phosphorylation in its receiver domain. In vivo, when a C-terminal DNA-binding domain lacking the N-terminal phospho-accepting (or receiver) domain was aberrantly expressed, the resulting transgenic plants showed characteristic anomalies during development of apical parts. The observed anomalies included "unusual proliferation of tissues in cotyledons" and "outgrowth of adventitious shoots near cotyledons". These results with regard to the functions of ARR11 are mainly discussed in comparison with those of the previously characterized type-B response regulators.

Expression of chaA, a sodium ion extrusion system of Escherichia coli, is regulated by osmolarity and pH. Reviewed

Shijuku T, Yamashino T, Ohashi H, Saito H, Kakegawa T, Ohta M, Kobayashi H

Biochim. Biophys. Acta. Vol. 1556 ( 2-3 ) page： 142-148 2002.12

Language：English Publishing type：Research paper (scientific journal)

ChaA, one of the sodium ion extrusion systems of Escherichia coli, was found to function at high pH [Biochim. Biophys. Acta 1363 (1998) 231]. A chaA-lacZ transcriptional fusion gene was constructed using chaA of E. coli O157:H7 and its expression was observed in strains derived from E. coli K12. The fusion gene was expressed at high pH and was induced by the addition of NaCl, KCl or sucrose. The amount of chaA mRNA measured by reverse transcription-polymerase chain reaction (RT-PCR) was increased by the addition of sucrose to alkaline growth medium. These results suggested that chaA expression was regulated by medium osmolarity and pH.

Compilation and characterization of a novel WNK family of protein kinases in Arabiodpsis thaliana with reference to circadian rhythms Reviewed

Nakamichi N, Murakami-Kojima M, Sato E, Kishi Y, Yamashino T, Mizuno T

Biosci. Biotechnol. Biochem. Vol. 66 ( 11 ) page： 2429-2439 2002.11

Language：English Publishing type：Research paper (scientific journal)

The complete genome sequence of Arabidopsis thaliana revealed that this higher plant has a tremendous number of protein kinases. We recently isolated a novel type of protein kinase, named AtWNK1, which shows an in vitro ability to phosphorylate the APRR3 member of the APRR1/TOC1 quintet that has been implicated in a mechanism underlying circadian rhythms in Arabidopsis. We here address two issues, one general and one specific, as to this novel protein kinase. We first asked the general question of how many WNK family members are present in this higher plant, then whether or not other members are also relevant to circadian rhythms. The results of our analyses showed that Arabidopsis has at least 9 members of the WNK1 family of protein kinases (designated here as WNK1 to WNK9), the structural design of which is clearly distinct from those of other known protein kinases, such as receptor-like kinases and mitogen-activated protein kinases. They were examined with special reference to the circadian-related APRR1/TOC1 quintet. It was found that not only the transcription of the WNK1 gene, but also those of three other members (WNK2, WNK4, and WNK6) are under the control of circadian rhythms. These results suggested that certain members of the WNK family of protein kinases might play roles in a mechanism that generates circadian rhythms in Arabidopsis.

Aberrant expression of the Arabidopsis circadian-regulated APRR5 gene belonging to the APRR1/TOC1 quintet results in early flowering and hypersensitiveness to light in early photomorphogenesis Reviewed

Sato E, Nakamichi N, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 43 ( 11 ) page： 1374-1385 2002.11

Language：English Publishing type：Research paper (scientific journal)

In Arabidopsis thaliana, the transcripts of the APRR1/TOC1 family genes each start accumulating after dawn rhythmically and one after another at intervals in the order of APRR9-->APRR7-->APRR5-->APRR3-->APRR1/TOC1 under continuous light. Except for the well-characterized APRR1/TOC1, however, no evidence has been provided that other APRR1/TOC1 family genes are indeed implicated in the mechanisms underlying circadian rhythms. We here attempted to provide such evidence by characterizing transgenic plants that constitutively express the APRR5 gene. The resulting APRR5-overexpressing (APRR5-ox) plants showed intriguing properties with regard to not only circadian rhythms, but also control of flowering time and light response. First, the aberrant expression of APRR5 in such transgenic plants resulted in a characteristic phenotype with regard to transcriptional events, in which free-running rhythms were considerably altered for certain circadian-regulated genes, including CCA1, LHY, APRR1/TOC1, other APRR1/TOC1 members, GI and CAB2, although each rhythm was clearly sustained even after plants were transferred to continuous light. With regard to biological events, APRR5-ox plants flowered much earlier than wild-type plants, more or less, in a manner independent of photoperiodicity (or under short-day conditions). Furthermore, APRR5-ox plants showed an SRL (short-hypocotyls under red light) phenotype that is indicative of hypersensitiveness to red light in early photomorphogenesis. Both APRR1-ox and APRR9-ox plants also showed the same phenotype. Therefore, APRR5 (together with APRR1/TOC1 and APRR9) must be taken into consideration for a better understanding of the molecular links between circadian rhythms, control of flowering time through the photoperiodic long-day pathway, and also light signaling-controlled plant development.

Aberrant expression of the light-inducible and circadian-regulated APRR9 gene belonging to the circadian-associated APRR1/TOC1 quintet results in the phenotype of early flowering in Arabidopsis thaliana Reviewed

Matsushika A, Imamura A, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 43 ( 8 ) page： 833-843 2002.8

Language：English Publishing type：Research paper (scientific journal)

Several Arabidopsis genes have been proposed to encode potential clock-associated components, including the Myb-related CCA1 and LHY transcription factors and a member (APRR1/TOC1) of the family of pseudo-response regulators. We previously showed that transcripts of the APRR1/TOC1 family genes each start accumulating after dawn rhythmically and sequentially at intervals in the order of APRR9-->APRR7-->APRR5-->APRR3-->APRR1/TOC1, under the conditions of continuous light. Nevertheless, no evidence has been provided that each member of the APRR1/TOC1 quintet, except for APRR1/TOC1, is indeed relevant to the mechanisms underlying circadian rhythms. Here we attempt to provide such evidence by characterizing transgenic plants that aberrantly (or constitutively) express the APRR9 gene in a manner independent of circadian rhythms. The resulting APRR9-ox plants showed intriguing phenotypes with regard to circadian rhythms, in two aspects. First, the aberrant expression of APRR9 resulted in a characteristic phenotype with regard to transcriptional events, in which short-period rhythms were commonly observed for certain circadian-regulated genes, including CCA1, LHY, APRR1/TOC1, other APRR1/TOC1 members, ELF3, and CAB2. With regard to biological consequences, such APRR9-ox plants flowered much earlier than wild-type plants, in a manner independent of photoperiodicity (or under short-day conditions). These results suggest that APRR9 (and perhaps other members of the APRR1/TOC1 quintet) must also be taken into consideration for a better understanding of the molecular mechanisms underlying circadian rhythms, and also underlying control of the flowering time through the photoperiodic long-day pathway.

The APRR3 component of the clock-associated APRR1/TOC1 quintet is phosphorylated by a novel protein kinase belonging to the WNK family, the gene for which is also transcribed rhythmically in Arabidopsis thaliana Reviewed

Murakami-Kojima M, Nakamichi N, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 43 ( 6 ) page： 675-683 2002.6

Language：English Publishing type：Research paper (scientific journal)

In higher plants, clock-controlled circadian rhythms are a longstanding issue in physiology, and a newly emerging paradigm of molecular biology. In the model higher plant Arabidopsis thaliana, several genes have been proposed to encode potential clock-associated components, including a member (APRR1/TOC1) of the pseudo-response regulator family. We previously showed that transcripts of the APRR1/TOC1 family start accumulating after dawn rhythmically and sequentially at approximately 2 h intervals in the order of APRR9-->APRR7-->APRR5-->APRR3-->APRR1/ TOC1. This and other results led us to propose that this APRR1/TOC1 quintet might play coordinate roles in the mechanism underlying circadian rhythms in higher plants. To gain further insight as to such an idea, we here attempt to identify proteins that interact with one of the quintet members, APRR3. The identified component is a novel protein kinase, named WNK1, which is considerably similar to, but clearly distinct from, mitogen-activated protein kinases (MAPKs). It was found that APRR3 is a substrate of this novel protein kinase, the gene for which also shows a rhythmic transcription profile that is well coincident with the APRR3 rhythm. These findings give new insight into the mechanisms underlying the circadian rhythm in A. thaliana, providing a molecular link between the putative clock component, APRR3, and WNK1, a novel protein kinase that might be implicated as a signal transducer.

Involvement of surface polysaccharides in the organic acid resistance of Shiga Toxin-producing Escherichia coli O157:H7. Reviewed

Barua S, Yamashino T, Hasegawa T, Yokoyama K, Torii K, Ohta M

Mol. Microbiol. Vol. 43 ( 3 ) page： 629-640 2002.2

Language：English Publishing type：Research paper (scientific journal)

In general, wild Escherichia coli strains can grow effectively under moderately acidic organic acid-rich conditions. We found that the Shiga Toxin-producing E. coli (STEC) O157:H7 NGY9 grows more quickly than a K-12 strain in Luria-Bertani (LB)-2-morpholinoethanesulphonic acid (MES) broth supplemented with acetic acid (pH 5.4). Hypothesizing that the resistance of STEC O157:H7 to acetic acid is as a result of a mechanism(s) other than those known, we screened for STEC mutants sensitive to acetic acid. NGY9 was subjected to mini-Tn5 mutagenesis and, from 50,000 colonies, five mutants that showed a clear acetic acid-sensitive phenotype were isolated. The insertion of mini-Tn5 in three mutants occurred at the fcl, wecA (rfe) and wecB (rffE) genes and caused loss of surface O-polysaccharide, loss of both O-polysaccharide and enterobacterial common antigen (ECA) and loss of ECA respectively. The other two mutants showed inactivation of the waaG (rfaG) gene but at different positions that caused a deep rough mutant with loss of the outer core oligosaccharide of lipopolysaccharide (LPS) as well as phenotypic loss of O-polysaccharide and ECA. With the introduction of plasmids carrying the fcl, wecA, wecB and waaG genes, respectively, all mutants were complemented in their production of O-polysaccharide and ECA, and normal growth was restored in organic acid-rich culture conditions. We also found that the growth of Salmonella LPS mutants Ra, Rb1, Rc, Rd1, Rd2 and Re was suppressed in the presence of acetic acid compared with that of the parents. These results suggest that the full expression of LPS (including O-polysaccharide) and ECA is indispensable to the resistance against acetic acid and other short chain fatty acids in STEC O157:H7 and Salmonella. To the best of our knowledge, this is a newly identified physiological role for O-polysaccharide and ECA as well as an acid resistance mechanism.

The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: I. Characterization with APRR1-overexpressing plants. Reviewed

Makino S, Matsushika A, Kojima M, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 43 ( 1 ) page： 58-69 2002.1

Language：English

Several Arabidopsis genes have been proposed to encode potential clock-associated components, including the Myb-related CCA1 and LHY transcription factors and a member of the novel family of pseudo response regulators (APRR1/TOC1). We previously showed that mRNAs of the APRR1/TOC1 family of genes start accumulating after dawn rhythmically and sequentially at approximately 2 h intervals in the order: APRR9--> APRR7-->APRR5-->APRR3-->APRR1/TOC1. Here we constructed APRR1-overexpressing (APRR1-ox) plants, and examined certain circadian profiles for APRRs, CCA1, LHY, GI, CCR2, and CAB2. The free-running circadian rhythms of the APRR1/TOC1 family of genes, including APRR1, were dampened in APRR1-ox plants. In particular, the light-inducible expression of APRR9 was severely repressed in APRR1-ox plants, suggesting that there is a negative APRR1-->APRR9 regulation. The free-running robust rhythm of CAB2 was also dampened in APRR1-ox. The circadian profiles of potential clock-associated genes, CCA1, LHY, GI, and CCR2 were all markedly altered in APRR1-ox, each in characteristic fashion. To gain further insight into the molecular function of APRR1, we then identified a novel Myc-related bHLH transcription factor, which physically associated with APRR1. This protein (named PIL1) is similar in its amino acid sequence to PIF3, which has been identified as a phytochrome-interacting transcription factor. These results are discussed in relation to the current idea that APRR1 (TOC1) plays a role within, or close to, the Arabidopsis central oscillator.

The APRR1/TOC1 quintet implicated in circadian rhythms of Arabidopsis thaliana: II. Characterization with CCA1-overexpressing plants Reviewed

Matsushika A, Makino S, Kojima M, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 43 ( 1 ) page： 118-122 2002.1

Language：English Publishing type：Research paper (scientific journal)

We previously identified a novel class of proteins, named pseudo-response regulators (APRRs) in Arabidopsis thaliana, each of which (APRR1, APRR3, APRR5, APRR7, and APRR9) has an intriguing structural design containing an N-terminal pseudo receiver domain and a C-terminal CONSTANS motif. Among them, APRR1 is identical to TOC1, previously proposed to be a candidate component of an Arabidopsis circadian clock. Intriguingly, expressions of the APRR1/TOC1 family of genes are under control of coordinate circadian rhythms at the level of transcription, in the manner that each APRR-transcript starts accumulating sequentially after dawn with 2 to 3 h intervals in the order: APRR9-->APRR7-->APRR5-->APRR3-->APRR1/TOC1. Here we examined this circadian-related event, "circadian waves of the APRR1/TOC1 quintet", by employing CCA1-overexpression (CCA1-ox) transgenic plants, based on the fact that CCA1 is a well-characterized and the most plausible oscillator component. It was found that aberrant overexpression of the CCA1 gene severely perturbed free-running and sequential rhythms of the APRR1/TOC1 family of genes. In the accompanying paper, it was shown that overexpression of APRR1 also results in a marked alteration of the CCA1 circadian rhythm, and vice versa. Taken together, it was suggested that there are intimate and mutual links between these two types of circadian-associated components (APRRs and CCA1).

An Arabidopsis histidine-containing phosphotransfer (HPt) factor implicated in phosphorelay signal transduction: overexpression of AHP2 in plants results in hypersensitiveness to cytokinin Reviewed

Suzuki T, Ishikawa K, Yamashino T, Mizuno T

Plant Cell Physiol. Vol. 43 ( 1 ) page： 123-129 2002.1

Language：English Publishing type：Research paper (scientific journal)

Histidine-containing phosphotransfer (HPt) factors from Arabidopsis thaliana, designated as AHPs, function most likely in concert with histidine (His)-kinases (HKs) and response regulators (RRs) in certain multistep histidine (His)-->aspartate (Asp) phosphorelays that are involved in the signal transduction mechanisms, by which plant cells appear to respond to certain hormonal stimuli, including cytokinin. Although some previous in vitro results from studies on Arabidopsis AHPs (AHP1 to AHP5) supported this hypothesis, it has not yet been proven. To this end, here we constructed transgenic plants that contained the AHP2 protein in a considerably higher amount than in wild-type plants. Such AHP2-overexpressing young seedlings were examined in comparison with wild-type plants, with special reference to hormone responses; particularly, their inhibitory effects on root elongation of plants grown on agar-plates, and also hypocotyl elongation of etiolated seedlings grown in the dark. The results of this study suggested that AHP2-overexpressing plants showed a characteristic phenotype of cytokinin-hypersensitive. These in vivo observations were best interpreted by assuming that the AHP factor(s) is somehow implicated, if not directly, in a cytokinin-mediated His-->Asp phosphorelay signaling in Arabidopsis.

Resolution of Escherichia coli O157:H7 that contaminated radish sprouts in two outbreaks by two-dimensional gel electrophoresis.

"Yokoyama K, Iinuma Y, Kawano Y, Nakano M, Kawagishi M, Yamashino T, Hasegawa T, Ohta M"

Curr. Microbiol. Vol. 43 ( 5 ) page： 311-315 2001.11

Characterization of the RcsC-->YojN-->RcsB phosphorelay signaling pathway involved in capsular synthesis in Escherichia coli.

"Chen MH, Takeda S, Yamada H, Ishii Y, Yamashino T, Mizuno T"

Biosci. Biotechnol. Biochem. Vol. 65 ( 10 ) page： 2364-2367 2001.10

The Arabidopsis AHK4 histidine kinase is a cytokinin-binding receptor that transduces cytokinin signals across the membrane.

"Yamada H, Suzuki T, Terada K, Takei K, Ishikawa K, Miwa K, Yamashino T, Mizuno T"

Plant Cell Physiol. Vol. 42 ( 9 ) page： 1017-1023 2001.9

Postantibiotic suppression effect of macrolides on the expression of flagellin in Pseudomonas aeruginosa and Proteus mirabilis.

"Kawamura-Sato K, Iinuma Y, Hasegawa T, Yamashino T, Ohta M."

J. Infect. Chemother. Vol. 7 ( 1 ) page： 51-54 2001.3

Proteolytic cleavage of staphylococcal exoproteins analyzed by two-dimensional gel electrophoresis.

"Kawano Y, Kawagishi M, Nakano M, Mase K, Yamashino T, Hasegawa T, Ohta M."

Microbiol. Immunol. Vol. 45 ( 4 ) page： 285-90 2001.1

Production of shiga toxin by Escherichia coli measured with reference to the membrane vesicle-associated toxins.

"Yokoyama K, Horii T, Yamashino T, Hashikawa S, Barua S, Hasegawa T, Watanabe H, Ohta M."

FEMS Microbiol. Lett. Vol. 192 ( 1 ) page： 139-144 2000.11

Effect of subinhibitory concentrations of macrolides on expression of flagellin in Pseudomonas aeruginosa and Proteus mirabilis.

"Kawamura-Sato K, Iinuma Y, Hasegawa T, Horii T, Yamashino T, Ohta M."

Antimicrob. Agents Chemother. Vol. 44 ( 10 ) page： 2869-2872 2000.10

Rapid isolation and identification of staphylococcal exoproteins by reverse phase capillary high performance liquid chromatography-electrospray ionization mass spectrometry.

"Kawano Y, Ito Y, Yamakawa Y, Yamashino T, Horii T, Hasegawa T, Ohta M."

FEMS Microbiol. Lett. Vol. 189 ( 1 ) page： 103-108 2000.8

Deletion of the yhhP gene results in filamentous cell morphology in Escherichia coli.

Ishii Y, Yamada H, Yamashino T, Ohashi K, Katoh E, Shindo H, Yamazaki T, Mizuno T

Biosci. Biotechnol. Biochem. Vol. 64 ( 4 ) page： 799-807 2000.4

Firm adherence of Staphylococcus aureus and Staphylococcus epidermidis to human hair and effect of detergent treatment.

"Mase K, Hasegawa T, Horii T, Hatakeyama K, Kawano Y, Yamashino T, Ohta M."

Microbiol. Immunol. Vol. 44 ( 8 ) page： 653-656 2000.1

The yhhP gene encoding a small ubiquitous protein is fundamental for normal cell growth of Escherichia coli.

"Yamashino T, Isomura M, Ueguchi C, Mizuno T"

J. Bacteriol. Vol. 180 ( 8 ) page： 2257-61 1998.4

Quantitative control of the stationary phase-specific sigma factor σ^s, in Escherichia coli : involvement of the nucleoid protein H-NS

EMBO J. Vol. 14 page： 594-602 1995

An analogue of the Dna J molecular chaperone whose expression is controlled by σ^s during the stationary phase and phosphate starvation in Escherichia coli

Mol. Microbiol. Vol. 13 page： 475-483 1994

Expression of the Escherichia coli Dimorphic Glutamic Acid Decarboxylases is Regulated by the Nucleoid Protein H-NS Reviewed

Biosci. Biotech. Biochem. Vol. 57 page： 1568-1569 1993

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