Faculty Profiles - TAZAKI Akira

Papers - TAZAKI Akira

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Pseudo typed baculovirus is an effective gene expression tool for studying Reviewed

Catarina R. Oliveira, Regis Lemaitre, Prayag Murawala, Akira Tazaki, David N. Drechsel, Elly M. Tanaka

DEVELOPMENTAL BIOLOGY Vol. 433 ( 2 ) page： 262 - 275 2018.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Axolotls can regenerate complex structures through recruitment and remodeling of cells within mature tissues. Accessing the underlying mechanisms at a molecular resolution is crucial to understand how injury triggers regeneration and how it proceeds. However, gene transformation in adult tissues can be challenging. Here we characterize the use of pseudotyped baculovirus (BV) as an effective gene transfer method both for cells within mature limb tissue and within the blastema. These cells remain competent to participate in regeneration after transduction. We further characterize the effectiveness of BV for gene overexpression studies by overexpressing Shh in the blastema, which yields a high penetrance of classic polydactyly phenotypes. Overall, our work establishes BV as a powerful tool to access gene function in axolotl limb regeneration.

DOI： 10.1016/j.ydbio.2017.10.008

Serum Proteases Potentiate BMP-Induced Cell Cycle Re-entry of Dedifferentiating Muscle Cells during Newt Limb Regeneration Reviewed

Ines Wagner, Heng Wang, Philipp M. Weissert, Werner L. Straube, Anna Shevchenko, Marc Gentzel, Goncalo Brito, Akira Tazaki, Catarina Oliveira, Takuji Sugiura, Andrej Shevchenko, Andras Simon, David N. Drechsel, Elly M. Tanaka

DEVELOPMENTAL CELL Vol. 40 ( 6 ) page： 608 - 617.e6 2017.3

Language：English Publishing type：Research paper (scientific journal) Publisher：CELL PRESS

Limb amputation in the newt induces myofibers to dedifferentiate and re-enter the cell cycle to generate proliferative myogenic precursors in the regeneration blastema. Here we show that bone morphogenetic proteins (BMPs) and mature BMPs that have been further cleaved by serum proteases induce cell cycle entry by dedifferentiating newt muscle cells. Protease-activated BMP4/7 heterodimers that are present in serum strongly induced myotube cell cycle reentry with protease cleavage yielding a 30-fold potency increase of BMP4/7 compared with canonical BMP4/7. Inhibition of BMP signaling via musclespecific dominant-negative receptor expression reduced cell cycle entry in vitro and in vivo. In vivo inhibition of serine protease activity depressed cell cycle re-entry, which in turn was rescued by cleaved-mimic BMP. This work identifies a mechanism of BMP activation that generates blastema cells from differentiated muscle.

DOI： 10.1016/j.devcel.2017.03.002

The posterior neural plate in axolotl gives rise to neural tube or turns anteriorly to form somites of the tail and posterior trunk Reviewed

Yuka Taniguchi, Thomas Kurth, Susanne Weiche, Saskia Reichelt, Akira Tazaki, Srikanth Perike, Verena Kappert, Hans-Henning Epperlein

DEVELOPMENTAL BIOLOGY Vol. 422 ( 2 ) page： 155 - 170 2017.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Classical grafting experiments in the Mexican axolotl had shown that the posterior neural plate of the neurula is no specified neuroectoderm but gives rise to somites of the tail and posterior trunk. The bipotentiality of this region with neuromesodermal progenitor cell populations was revealed more recently also in zebrafish, chick, and mouse. We reinvestigated the potency of the posterior plate in axolotl using grafts from transgenic embryos, immunohistochemistry, and in situ hybridization. The posterior plate is brachyury-positive except for its more anterior parts which express sox2. Between anterior and posterior regions of the posterior plate a small domain with sox2+ and bra+ cells exists. Lineage analysis of grafted GFP-labeled posterior plate tissue revealed that posterior GFP+ cells move from dorsal to ventral, form the posterior wall, turn anterior bilaterally, and join the gastrulated paraxial presomitic mesoderm. More anterior sox2+/GFP+ cells, however, are integrated into the developing spinal cord. Tail notochord is formed from axial mesoderm involuted already during gastrulation. Thus the posterior neural plate is a postgastrula source of paraxial mesoderm, which performs an anterior turn, a novel morphogenetic movement. More anterior plate cells, in contrast, do not turn anteriorly but become specified to form tail spinal cord.

DOI： 10.1016/j.ydbio.2016.12.023

Mesodermal origin of median fin mesenchyme and tail muscle in amphibian larvae Reviewed

Yuka Taniguchi, Thomas Kurth, Daniel Meulemans Medeiros, Akira Tazaki, Robert Ramm, Hans-Henning Epperlein

SCIENTIFIC REPORTS Vol. 5 page： 11428 2015.6

Language：English Publishing type：Research paper (scientific journal) Publisher：NATURE PUBLISHING GROUP

Mesenchyme is an embryonic precursor tissue that generates a range of structures in vertebrates including cartilage, bone, muscle, kidney, and the erythropoietic system. Mesenchyme originates from both mesoderm and the neural crest, an ectodermal cell population, via an epithelial to mesenchymal transition (EMT). Because ectodermal and mesodermal mesenchyme can form in close proximity and give rise to similar derivatives, the embryonic origin of many mesenchyme-derived tissues is still unclear. Recent work using genetic lineage tracing methods have upended classical ideas about the contributions of mesodermal mesenchyme and neural crest to particular structures. Using similar strategies in the Mexican axolotl (Ambystoma mexicanum), and the South African clawed toad (Xenopus laevis), we traced the origins of fin mesenchyme and tail muscle in amphibians. Here we present evidence that fin mesenchyme and striated tail muscle in both animals are derived solely from mesoderm and not from neural crest. In the context of recent work in zebrafish, our experiments suggest that trunk neural crest cells in the last common ancestor of tetrapods and ray-finned fish lacked the ability to form ectomesenchyme and its derivatives.

DOI： 10.1038/srep11428

Fundamental Differences in Dedifferentiation and Stem Cell Recruitment during Skeletal Muscle Regeneration in Two Salamander Species Reviewed

Tatiana Sandoval-Guzman, Heng Wang, Shahryar Khattak, Maritta Schuez, Kathleen Roensch, Eugeniu Nacu, Akira Tazaki, Alberto Joven, Elly M. Tanaka, Andras Simon

CELL STEM CELL Vol. 14 ( 2 ) page： 174 - 87 2014.2

Language：English Publishing type：Research paper (scientific journal) Publisher：CELL PRESS

Salamanders regenerate appendages via a progenitor pool called the blastema. The cellular mechanisms underlying regeneration of muscle have been much debated but have remained unclear. Here we applied Cre-loxP genetic fate mapping to skeletal muscle during limb regeneration in two salamander species, Notophthalmus viridescens (newt) and Ambystoma mexicanum (axolotl). Remarkably, we found that myofiber dedifferentiation is an integral part of limb regeneration in the newt, but not in axolotl. In the newt, myofiber fragmentation results in proliferating, PAX7(-) mononuclear cells in the blastema that give rise to the skeletal muscle in the new limb. In contrast, myofibers in axolotl do not generate proliferating cells, and do not contribute to newly regenerated muscle; instead, resident PAX7(+) cells provide the regeneration activity. Our results therefore show significant diversity in limb muscle regeneration mechanisms among salamanders and suggest that multiple strategies may be feasible for inducing regeneration in other species, including mammals.

DOI： 10.1016/j.stem.2013.11.007

Muscle and connective tissue progenitor populations show distinct Twist1 and Twist3 expression profiles during axolotl limb regeneration Reviewed

Martin Kragl, Kathleen Roensch, Ina Nuesslein, Akira Tazaki, Yuka Taniguchi, Hiroshi Tarui, Tetsutaro Hayashi, Kiyokazu Agata, Elly M. Tanaka

DEVELOPMENTAL BIOLOGY Vol. 373 ( 1 ) page： 196 - 204 2013.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Limb regeneration involves re-establishing a limb development program from cells within adult tissues. Identifying molecular handles that provide insight into the relationship between cell differentiation status and cell lineage is an important step to study limb blastema cell formation. Here, using single cell PCR, focusing on newly isolated Twist1 sequences, we molecularly profile axolotl limb blastema cells using several progenitor cell markers. We link their molecular expression profile to their embryonic lineage via cell tracking experiments. We use in situ hybridization to determine the spatial localization and extent of overlap of different markers and cell types. Finally, we show by single cell PCR that the mature axolotl limb harbors a small but significant population of Twist1(+) cells. (C) 2012 Published by Elsevier Inc.

DOI： 10.1016/j.ydbio.2012.10.019

Comparative Transcriptional Profiling of the Axolotl Limb Identifies a Tripartite Regeneration-Specific Gene Program Reviewed

Dunja yy Knapp, Herbert Schulz, Cynthia Alexander Rascon, Michael Volkmer, Juliane Scholz, Eugen Nacu, Mu Le, Sergey Novozhilov, Akira Tazaki, Stephanie Protze, Tina Jacob, Norbert Hubner, Bianca Habermann, Elly M. Tanaka

PLOS ONE Vol. 8 ( 5 ) page： e61352 2013

Language：English Publishing type：Research paper (scientific journal) Publisher：PUBLIC LIBRARY SCIENCE

Understanding how the limb blastema is established after the initial wound healing response is an important aspect of regeneration research. Here we performed parallel expression profile time courses of healing lateral wounds versus amputated limbs in axolotl. This comparison between wound healing and regeneration allowed us to identify amputation-specific genes. By clustering the expression profiles of these samples, we could detect three distinguishable phases of gene expression - early wound healing followed by a transition-phase leading to establishment of the limb development program, which correspond to the three phases of limb regeneration that had been defined by morphological criteria. By focusing on the transition-phase, we identified 93 strictly amputation-associated genes many of which are implicated in oxidative-stress response, chromatin modification, epithelial development or limb development. We further classified the genes based on whether they were or were not significantly expressed in the developing limb bud. The specific localization of 53 selected candidates within the blastema was investigated by in situ hybridization. In summary, we identified a set of genes that are expressed specifically during regeneration and are therefore, likely candidates for the regulation of blastema formation.

DOI： 10.1371/journal.pone.0061352

Reconstitution of the central and peripheral nervous system during salamander tail regeneration Reviewed

Levan Mchedlishvili, Vladimir Mazurov, Kathrin S. Grassme, Kerstin Goehler, Bernhard Robl, Akira Tazaki, Kathleen Roensch, Annett Duemmler, Elly M. Tanaka

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Vol. 109 ( 34 ) page： E2258 - 66 2012.8

Language：English Publishing type：Research paper (scientific journal) Publisher：NATL ACAD SCIENCES

We show that after tail amputation in Ambystoma mexicanum (Axolotl) the correct number and spacing of dorsal root ganglia are regenerated. By transplantation of spinal cord tissue and non-clonal neurospheres, we show that the central spinal cord represents a source of peripheral nervous system cells. Interestingly, melanophores migrate from preexisting precursors in the skin. Finally, we demonstrate that implantation of a clonally derived spinal cord neurosphere can result in reconstitution of all examined cell types in the regenerating central spinal cord, suggesting derivation of a cell with spinal cord stem cell properties.

DOI： 10.1073/pnas.1116738109

The Analysis of the Expression of a Novel Gene, Xenopus polka dots, which was Expressed in the Embryonic and Larval Epidermis during Early Development Reviewed

Shunsuke Yoshii, Masahiro Yamaguchi, Yuichiro Oogata, Akira Tazaki, Makoto Mochii, Shintaro Suzuki, Tsutomu Kinoshita

ZOOLOGICAL SCIENCE Vol. 28 ( 11 ) page： 809 - 16 2011.11

Language：English Publishing type：Research paper (scientific journal) Publisher：ZOOLOGICAL SOC JAPAN

The epidermis serves as a barrier protecting organs and tissues from the environment, and comprises many types of cells. A cell renewal system is established in epidermis: old epithelial cells are replaced by newly differentiated cells, which are derived from epidermal stem cells located near basement membrane. In order to examine the mechanism of epidermal development, we isolated a novel gene expressed in Xenopus epidermis and named the gene Xenopus polka dots (Xpod) from its polka dot-like expression pattern throughout larval periods. Several immunohistochemical examinations showed that the Xpod-expressing cell type is neither p63-positive epidermal stem cells, nor the alpha-tubulin-positive ciliated cells, but a subset of the foxi1e-positive ionocytes. The forced gene expression of foxi1e caused the suppression of Xpod expression, while Xpod showed no effect on foxi1e expression. In a comparison of several osmotic conditions, we found that hypertonic culture caused the increase in number of the Xpod-expressing cell, whereas number of the foxi1e-expressing cells was reduced under the hypertonic condition. These results show the possibility that Xpod is involved in the establishment of a certain subpopulation of ionocytes under hypertonic conditions.

DOI： 10.2108/zsj.28.809

Germ-line mitochondria exhibit suppressed respiratory activity to support their accurate transmission to the next generation Reviewed

Naomi Kogo, Akira Tazaki, Yasuhiro Kashino, Keisuke Morichika, Hidefumi Orii, Makoto Mochii, Kenji Watanabe

DEVELOPMENTAL BIOLOGY Vol. 349 ( 2 ) page： 462 - 9 2011.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE

Mitochondria are accurately transmitted to the next generation through a female germ cell in most animals. Mitochondria produce most ATP, accompanied by the generation of reactive oxygen species (ROS). A specialized mechanism should be necessary for inherited mitochondria to escape from impairments of mtDNA by ROS. Inherited mitochondria are named germ-line mitochondria, in contrast with somatic ones. We hypothesized that germ-line mitochondria are distinct from somatic ones. The protein profiles of germ-line and somatic mitochondria were compared, using oocytes at two different stages in Xenopus laevis. Some subunits of ATP synthase were at a low level in germ-line mitochondria, which was confirmed immunologically. Ultrastructural histochemistry using 3,3'-diaminobenzidine (DAB) Showed that cytochrome c oxidase (COX) activity of germ-line mitochondria was also at a low level. Mitochondria in one oocyte were segregated into germ-line mitochondria and somatic mitochondria, during growth from stage I to VI oocytes. Respiratory activity represented by ATP synthase expression and COX activity was shown to be low during most of the long gametogenetic period. We propose that germ-line mitochondria that exhibit suppressed respiration alleviate production of ROS and enable transmission of accurate mtDNA from generation to generation. (C) 2010 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.ydbio.2010.11.021

Characterization of a Novel Type I Keratin Gene and Generation of Transgenic Lines With Fluorescent Reporter Genes Driven by Its Promoter/Enhancer in Xenopus laevis Reviewed

Ken-Ichi T. Suzuki, Keiko Kashiwagi, Motomu Ujihara, Takuzo Marukane, Akira Tazaki, Kenji Watanabe, Nobuhiko Mizuno, Yoko Ueda, Hisato Kondoh, Akihiko Kashiwagi, Makoto Mochii

DEVELOPMENTAL DYNAMICS Vol. 239 ( 12 ) page： 3172 - 81 2010.12

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

We investigated the characteristics of a novel type I keratin gene in Xenopus laevis during ontogenesis. The transcript was first detected in the posterior region at the late neurula stage, and then restricted to the fin and external gill during embryogenesis. To examine the transcriptional regulation of the keratin gene in vivo, we generated transgenic lines with fluorescent reporter genes driven by its 4.2-kb upstream sequence. The promoter/enhancer activity recapitulated the endogenous gene expression during embryogenesis. Sequential deletion analyses revealed that the regions proximal to the promoter were essential for fin-specific expression. Reporter expression was detected in various organs, including the fin and gill. In particular, robust expression was observed in the developing limbs and gill. The reporter fluorescence rapidly decreased with internal gill resorption during metamorphosis. The transgenic lines carrying the promoter/enhancer should represent valuable tools for elucidating the formation, development and resorption of various organs, especially the gill. Developmental Dynamics 239:3172-3181, 2010. (C) 2010 Wiley-Liss, Inc.

DOI： 10.1002/dvdy.22451

Perturbation of Notch/Suppressor of Hairless pathway disturbs migration of primordial germ cells in Xenopus embryo Reviewed

Keisuke Morichika, Kensuke Kataoka, Kohei Terayama, Akira Tazaki, Tsutomu Kinoshita, Kenji Watanabe, Makoto Mochii

DEVELOPMENT GROWTH & DIFFERENTIATION Vol. 52 ( 2 ) page： 235 - 44 2010.2

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

Primordial germ cells (PGCs) in Xenopus embryo are specified in the endodermal cell mass and migrate dorsally toward the future gonads. The role of the signal mediated by Notch and Suppressor of Hairless [Su(H)] was analyzed on the migrating PGCs at the tailbud stage. X-Notch-1 and X-Delta-1 are expressed in the migrating PGCs and surrounding endodermal cells, whereas X-Delta-2 and X-Serrate-1 are expressed preferentially in the PGCs. Suppression and constitutive activation of the Notch/Su(H) signaling in the whole endoderm region or selectively in the PGCs resulted in an increase in ectopic PGCs located in lateral or ventral regions. Knocking down of the Notch ligands by morpholino oligonucleotides revealed that X-Delta-2 was indispensable for the correct PGC migration. The ectopic PGCs seemed to have lost their motility in the Notch/Su(H) signal-manipulated embryos. Our results suggest that a cell-to-cell interaction via the Notch/Su(H) pathway has a significant role in the PGC migration by regulating cell motility.

DOI： 10.1111/j.1440-169X.2009.01164.x

Xenopus Wnt-5a induces an ectopic larval tail at injured site, suggesting a crucial role for noncanonical Wnt signal in tail regeneration Reviewed

Takuji Sugiura, Akira Tazaki, Naoto Ueno, Kenji Watanabe, Makoto Mochii

MECHANISMS OF DEVELOPMENT Vol. 126 ( 1-2 ) page： 56 - 67 2009.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Amputation of the larval tail of Xenopus injures the notochord, spinal cord, muscle masses, mesenchyme, and epidermis, induces the growth and differentiation of cells in those tissues, and results in tail regeneration. A dorsal incision in the larval tail injures the same tissues and induces cell growth and differentiation, but never results in the formation of any extra appendages. The first sign of tail regeneration is the multilayered wound epidermis and Xwnt-5a expression in the distal region, neither of which is observed in the recovering region after a dorsal incision. To evaluate the role of Xwnt-5a in tail regeneration, Xwnt-5a was overexpressed in the recovering region. When an animal cap injected with Xwnt-5a mRNA was grafted into the dorsal incision, an ectopic protrusion was formed. Morphological and molecular analyses revealed that the protrusion was an ectopic larval tail, which was equivalent to the regenerating tail but different from the tail that develops from the embryonic tail bud. Lineage labeling revealed that the major differentiated structures of the ectopic tail were formed from host cells, suggesting that Xwnt-5a induced host cells to make a complete tail. The ectopic tail was not induced by Xwnt-8 or Xwnt-11, demonstrating the specificity of Xwnt-5a in this process. A pharmacological study showed that JNK signaling is required in tail regeneration. These results support the proposition that Xwnt-5a plays an instructive role in larval tail regeneration via Wnt/JNK signaling. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.mod.2008.10.002

Presence of aquaporin and V-ATPase on the contractile vacuole of Amoeba proteus Reviewed

Eri Nishihara, Etsuo Yokota, Akira Tazaki, Hidefurni Orii, Maki Katsuhara, Kensuke Kataoka, Hisako Igarashi, Yoshinori Moriyama, Teruo Shimmen, Seiji Sonobe

BIOLOGY OF THE CELL Vol. 100 ( 3 ) page： 179 - 88 2008.3

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

Background information. The results of water permeability measurements suggest the presence of an AQP (aquaporin) in the membrane of the CV (contractile vacuole) in Amoeba proteus [Nishihara, Shimmen and Sonobe (2004) Cell Struct. Funct. 29, 85-90].Results. In the present study, we cloned an AQP gene from A. proteus [ApAQP (A. proteus AQP)] that encodes a 295-amino-acid protein. The protein has six putative TMs (transmembrane domains) and two NPA (Asn-Pro-Ala) motifs, which are conserved among various AQPs and are thought to be involved in the formation of water channels that span the lipid bilayer. Using Xenopus oocytes, we have demonstrated that the ApAQP protein product can function as a water channel. Immuncifluorescence microscopy with anti-ApAQP antibody revealed that ApAQP is detected on the CV membrane and on the vesicles around the CV. The presence of V-ATPase (vacuolar H+-ATPase) on the vesicle membrane around the CV was also detected.Conclusions. Our data on ApAQP allow us to provide the first informed explanation of the high water permeability of the CV membrane in amoeba. Moreover, the results suggest that vesicles possessing V-ATPase are involved in generating an osmotic gradient. Based on our findings, we propose a new hypothesis for the mechanism of CV function.

DOI： 10.1042/BC20070091

Spinal cord is required for proper regeneration of the tail in Xenopus tadpoles Reviewed

Yuka Taniguchi, Takuji Sugiura, Akira Tazaki, Kenji Watanabe, Makoto Mochii

DEVELOPMENT GROWTH & DIFFERENTIATION Vol. 50 ( 2 ) page： 109 - 20 2008.2

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

Tail regeneration in urodeles is dependent on the spinal cord (SC), but it is believed that anuran larvae regenerate normal tails without the SC. To evaluate the precise role of the SC in anuran tail regeneration, we developed a simple operation method to ablate the SC completely and minimize the damage to the tadpole using Xenopus laevis. The SC-ablated tadpole regenerated a twisted and smaller tail. These morphological abnormalities were attributed to defects in the notochord (NC), as the regenerated NC in the SC-ablated tail was short, slim and twisted. The SC ablation never affected the early steps of the regeneration, including closure of the amputated surface with epidermis and accumulation of the NC precursor cells. The proliferation rate of the NC precursor cells, however, was reduced, and NC cell maturation was retarded in the SC-ablated tail. These results show that the SC has an essential role in the normal tail regeneration of Xenopus larvae, especially in the proliferation and differentiation of the NC cells. Gene expression analysis and implantation of a bead soaked with growth factor showed that fibroblast growth factor-2 and -10 were involved in the signaling molecules, which were expressed in the SC and stimulated growth of the NC cells.

DOI： 10.1111/j.1440-169X.2007.00981.x

Visualization of the Xenopus primordial germ cells using a green fluorescent protein controlled by cis elements of the 3 ' untranslated region of the DEADSouth gene Reviewed

Kensuke Kataoka, Takeshi Yamaguchi, Hidefumi Orii, Akira Tazaki, Kenji Watanabe, Makoto Mochii

MECHANISMS OF DEVELOPMENT Vol. 123 ( 10 ) page： 746 - 60 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

We succeeded in visualization of the primordial germ cells (PGCs) in a living Xenopus embryo. The mRNA of the reporter Venus protein, fused to the 3' untranslated region (UTR) of DEADSouth, which is a component of the germ plasm in Xenopus eggs, was micro-injected into the vegetal pole of fertilized eggs and then the cells with Venus fluorescence were monitored during development. The behavior of the cells was identical to that previously described for PGCs. Almost all Venus-expressing cells were Xdazl-positive in the stage 48 tadpoles, indicating that they were PGCs. In addition, we found three sub-regions (A, B and C) in the 3' UTR, which were involved in the PGC-specific expression of the reporter protein. Sub-region A, which was identified previously as a localization signal for the germ plasm during oogenesis, participated in anchoring of the mRNA at the germ plasm and the degradation of the mRNA in the somatic cells. Sub-regions B and C were also involved in anchoring of the mRNA at the germ plasm. Sub-region B participated in the enhancement of translation. (c) 2006 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.mod.2006.07.006

Identification of asymmetrically localized transcripts along the animal-vegetal axis of the Xenopus egg Reviewed

K Kataoka, A Tazaki, A Kitayama, N Ueno, K Watanabe, M Mochii

DEVELOPMENT GROWTH & DIFFERENTIATION Vol. 47 ( 8 ) page： 511 - 21 2005.10

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-BLACKWELL

In many organisms, proper embryo development depends on the asymmetrical distribution of mRNA in the cytoplasm of the egg. Here we report comprehensive screening of RNA localized in the animal or vegetal hemisphere of the Xenopus egg. Macroarrays including over 40000 independent embryonic cDNA clones, representing at least 17000 unigenes, were differentially hybridized with labeled probes synthesized from the mRNA of animal or vegetal blastomeres. After two rounds of screening, we identified 33 clones of transcripts that may be preferentially distributed in the vegetal region of the early stage embryo, but transcripts localized in the animal region were not found. To assess the array results, we performed northern blot and quantitative real-time reverse transcription-polymerase chain reaction analysis. As a result, 21 transcripts of the 33 were confirmed to be localized in the vegetal region of the early stage embryo. Whole-mount in situ hybridization analysis revealed that 11 transcripts, including 7 previously reported genes, were localized in the vegetal hemisphere of the egg. These 11 transcripts were categorized into three groups according to their expression patterns in the egg. The first group, which contained four transcripts, showed uniform expression in the vegetal hemisphere, similar to VegT. The second group, which contained three transcripts, showed gradual expression from the vegetal pole to the equator, similar to Vg1. The last group, which contained three transcripts, was expressed at the germ plasm, similar to Xdazl. One transcript, Xwnt11, showed both the second and the third expression patterns.

DOI： 10.1111/j.1440-169X.2005.00826.x

Functional analysis of germ cell specific genes in Xenopus Reviewed

K. Kataoka, A. Tazaki, H. Orii, M. Mochii, K. Watanabe

MECHANISMS OF DEVELOPMENT Vol. 122 page： S119 - S120 2005.9

Macroarray-based analysis of tail regeneration in Xenopus laevis larvae Reviewed

A Tazaki, A Kitayama, C Terasaka, K Watanabe, N Ueno, M Mochii

DEVELOPMENTAL DYNAMICS Vol. 233 ( 4 ) page： 1394 - 404 2005.8

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY-LISS

Xenopus larvae possess a remarkable ability to regenerate their tails after they have been severed. To gain an understanding of the molecular mechanisms underlying tail regeneration, we performed a cDNA macroarray-based analysis of gene expression. A Xenopus cDNA macroarray representing 42,240 independent clones was differentially hybridized with probes synthesized from the total RNA of normal and regenerating tails. Temporal expression analysis revealed that the up-regulated genes could be grouped into early or late responding genes. A comparative expression analysis revealed that most genes showed similar expression patterns between tail development and regeneration. However, some genes showed regeneration-specific expression. Finally, we identified 48 up-regulated genes that fell into several categories based on their putative functions. These categories reflect the various processes that take place during regeneration, such as inflammation response, wound healing, cell proliferation, cell differentiation, and control of cell structure. Thus, we have identified a panel of genes that appear to be involved in the process of regeneration. (c) 2005 Wiley-Liss, Inc.

DOI： 10.1002/dvdy.20472

Differential gene expression between the embryonic tail bud and regenerating larval tail in Xenopus laevis.

Sugiura T, Taniguchi Y, Tazaki A, Ueno N, Watanabe K, Mochii M

Development, growth & differentiation Vol. 46 ( 1 ) page： 97 - 105 2004.2

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