研究者詳細 - 吉村　崇

論文 - 吉村　崇

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鳥類の時計遺伝子と光周性招待有り査読有り

安尾しのぶ, 渡邊美和, 海老原史樹文, 吉村崇

時間生物学 10 巻頁： 35-40 2004年

Expression of IKKα mRNA in the suprachiasmatic nucleus and circadian rhythms of mice lacking IKKα

Hayashi N, Yasuo S, Ebihara S, Yoshimura T

BRAIN RESEARCH 993 巻 ( 1-2 ) 頁： 217 - 221 2003年12月

出版者・発行元：Brain Research

In our previous study, quantitative trait locus (QTL) analysis using mice with abnormal circadian rhythm detected a suggestive QTL, which affects the length of free-running period, on the distal region of Chromosome 19. Among the candidate genes, we have focused on Ikkα gene and found that Ikkα mRNA is expressed in the mammalian circadian pacemaker, the suprachiasmatic nucleus (SCN) in the present study. Expression of Ikkα mRNA in the SCN indicated the possibility that IKKα is involved in the regulation of circadian clock. Therefore, to examine the role of IKKα in the regulation of circadian rhythms, we have further examined wheel-running activity rhythms under light-dark cycle and constant darkness, and circadian response to light. However, we could not detect any statistically significant difference between IKKα+/- mice and wild type mice. Roles of IKKα in the regulation of circadian system remains to be clarified in the future study. © 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.brainres.2003.09.007

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Ontogeny of circadian clock gene expression in the pineal and the suprachiasmatic nucleus of chick embryo

Okabayashi N, Yasuo S, Watanabe M, Namikawa T, Ebihara S, Yoshimura T

BRAIN RESEARCH 990 巻 ( 1-2 ) 頁： 231 - 234 2003年11月

出版者・発行元：Brain Research

Avian circadian rhythms are regulated by a multiple oscillatory system consisting of the pineal, the suprachiasmatic nucleus (SCN) and the eye. In the present study, ontogeny of circadian clock in the pineal and the SCN of chick embryo was examined using Per2 expression as a marker. A daily rhythmicity of Per2 expression was first detectable at embryonic day (ED) 18 in the pineal and at ED 16 in the SCN under light-dark (LD) cycles. The amplitude of the rhythmicity increased during the development. In contrast, little expression was observed during the development in constant darkness. These results suggest that although circadian clock matures by the end of the embryonic life in chicken, LD cycles are required for the expression of the Per2. © 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/S0006-8993(03)03531-5

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Light-induced hormone conversion of T<sub>4</sub> to T<sub>3</sub> regulates photoperiodic response of gonads in birds

Yoshimura T, Yasuo S, Watanabe M, Iigo M, Yamamura T, Hirunagi K, Ebihara S

NATURE 426 巻 ( 6963 ) 頁： 178 - 181 2003年11月

記述言語：英語出版者・発行元：Nature

Reproduction of many temperate zone birds is under photoperiodic control. The Japanese quail is an excellent model for studying the mechanism of photoperiodic time measurement because of its distinct and marked response to changing photoperiods. Studies on this animal have suggested that the mediobasal hypothalamus (MBH) is an important centre controlling photoperiodic time measurement. Here we report that expression in the MBH of the gene encoding type 2 iodothyronine deiodinase (Dio2), which catalyses the intracellular deiodination of thyroxine (T4) prohormone to the active 3,5,3′-triiodothyronine (T3), is induced by light in Japanese quail. Intracerebroventricular administration of T3 mimics the photoperiodic response, whereas the Dio2 inhibitor iopanoic acid prevents gonadal growth. These findings demonstrate that light-induced Dio2 expression in the MBH may be involved in the photoperiodic response of gonads in Japanese quail.

DOI： 10.1038/nature02117

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Circadian clock genes and photoperiodism: Comprehensive analysis of clock gene expression in the mediobasal hypothalamus, the Suprachiasmatic nucleus, and the pineal gland of Japanese quail under various light schedules

Yasuo S, Watanabe M, Okabayashi N, Ebihara S, Yoshimura T

ENDOCRINOLOGY 144 巻 ( 9 ) 頁： 3742 - 3748 2003年9月

出版者・発行元：Endocrinology

In birds, the mediobasal hypothalamus (MBH) including the infundibular nucleus, inferior hypothalamic nucleus, and median eminence is considered to be an important center that controls the photoperiodic time measurement. Here we show expression patterns of circadian clock genes in the MBH, putative suprachiasmatic nucleus (SCN), and pineal gland, which constitute the circadian pacemaker under various light schedules. Although expression patterns of clock genes were different between long and short photoperiod in the SCN and pineal gland, the results were not consistent with those under night interruption schedule, which causes testicular growth. These results indicate that different expression patterns of the circadian clock genes in the SCN and pineal gland are not an absolute requirement for encoding and decoding of seasonal information. In contrast, expression patterns of clock genes in the MBH were stable under various light conditions, which enables animals to keep a steady-state photoinducible phase.

DOI： 10.1210/en.2003-0435

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Sleep properties of CS mice with spontaneous rhythm splitting in constant darkness

Ebihara S, Miyazaki S, Sakamaki H, Yoshimura T

BRAIN RESEARCH 980 巻 ( 1 ) 頁： 121 - 127 2003年8月

出版者・発行元：Brain Research

In mice, genetic differences between inbred strains have been shown for several parameters of sleep and circadian activity rhythms. Our previous studies have demonstrated that CS mice have three remarkable characteristics in the circadian rhythm of locomotor activity: (1) high activity both during the day and night, (2) unstable freerunning period and (3) spontaneous rhythm splitting. In order to characterize sleep properties of CS mice, we compared circadian sleep patterns of CS with those of C57BL/6J and C3H/He mice which have normal circadian activity rhythms. Although C57BL/6J and C3H/He mice exhibited clear daily sleep-wake rhythms in the amount of each sleep parameter (Awake, SWS, PS), CS mice did not show clear rhythms in these parameters. The differences were particularly conspicuous in PS; no apparent day-night differences in the amount of PS, PS counts and PS interval (the interval between successive PS episodes) in CS mice. In addition, the ratio of PS to total sleep time was significantly larger in CS mice than other strains. Of these parameters, the most considerable was PS latency which was extremely short and direct transition from Awake to PS without appearance of SWS frequently occurred in these mice. These results indicate that CS mice may be useful for the understanding of sleep mechanisms and its dysfunction. © 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/S0006-8993(03)02947-0

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Unimodal circadian rhythm in the suprachiasmatic nucleus of behaviorally splitting mice

Watanabe T, Yoshimura T, McMahon DG, Ebihara S

NEUROSCIENCE LETTERS 345 巻 ( 1 ) 頁： 49 - 52 2003年7月

出版者・発行元：Neuroscience Letters

CS mice exhibit rhythm splitting in constant darkness (DD). To examine the anatomical and physiological bases of this phenomenon, mouse Period1 (mPer1)-driven green fluorescent protein (GFP) mice with rhythm splitting were produced by crossing CS and mPer1::GFP mice. GFP expression in the suprachiasmatic nucleus (SCN) slices showed a clear unimodal rhythm with the highest level at circadian time (CT) 8 or CT12 in splitting and non-splitting GFP mice under DD and no essential differences in the pattern of GFP expression were found between these mice. Moreover, there were no significant differences in the degree of symmetry in the paired rostral, central and caudal SCN between splitting and non-splitting mice. These results indicate that behavioral rhythm splitting in CS mice does not reflect the pattern of clock gene expression in the SCN. © 2003 Elsevier Science Ireland Ltd. All rights reserved.

DOI： 10.1016/S0304-3940(03)00484-1

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Ontogeny of circadian clock gene expression in the pineal gland and the suprachiasmatic nucleus of chick embryo

"N. Okabayashi, S. Yasuo, M. Watanabe, T. Namikawa, S. Ebihara, T. Yoshimura"

Brain Research 990 巻頁： 231-234 2003年1月

Expression of IKKalpha mRNA in the suprachiasmatic nucleus and circadian rhythms of mice lacking IKKalpha 査読有り

Hayashi N, Yasuo S, Ebihara S, Yoshimura T

Brain Research 993 巻頁： 217-221 2003年1月

Circadian clock genes and photoperiodism: Comprehensive analysis of clock gene expression in the mediobasal hypothalamus, suprachiasmatic nucleus, and the pineal gland of Japanese quail under various light schedules 査読有り

Yasuo S, Watanabe M, Okabayashi N, Ebihara S, Yoshimura T

Endocrinology 144 巻頁： 3742-3748 2003年1月

Unimodal circadian rhythm in the suprachiasmatic nucleus of behaviorally splitting mice 査読有り

Watanabe T, Yoshimura T, McMahon D.G., Ebihara S

Neuroscience Letters 345 巻頁： 49-52 2003年1月

Mapping quantitative trait loci affecting circadian photosensitivity in retinally degenerate mice

Yoshimura T, Yokota Y, Ishikawa A, Yasuo SD, Hayashi N, Suzuki T, Okabayashi N, Namikawa T, Ebihara S

JOURNAL OF BIOLOGICAL RHYTHMS 17 巻 ( 6 ) 頁： 512 - 519 2002年12月

Effect of melatonin administration on qPer2, qPer3, and qClock gene expression in the suprachiasmatic nucleus of Japanese quail

Yasuo S, Yoshimura T, Bartell PA, Iigo M, Makino E, Okabayashi N, Ebihara S

EUROPEAN JOURNAL OF NEUROSCIENCE 16 巻 ( 8 ) 頁： 1541 - 1546 2002年10月

ウズラの排卵・放卵周期の制御機構招待有り

吉村崇

日本時間生物学会会誌 8 巻頁： 38-41 2002年1月

QTL解析招待有り

"海老原史樹文,鈴木亨,吉村崇,石川明"

分子精神医学 2 巻頁： 78-80 2002年1月

脊椎動物の概日光受容招待有り

"海老原史樹文,吉村崇"

神経研究の進歩 45 巻頁： 797-805 2001年10月

Quantitative trait locus analysis of abnormal circadian period in CS mice

Suzuki T, Ishikawa A, Yoshimura T, Namikawa T, Abe H, Honma S, Honma K, Ebihara S

MAMMALIAN GENOME 12 巻 ( 4 ) 頁： 272 - 277 2001年4月

出版者・発行元：Mammalian Genome

CS mice show a free-running period (τ) longer than 24 h and rhythm splitting in constant darkness (DD). These features in behavioral circadian rhythms are distinctive as compared with other inbred strains of mice, which exhibit robust free-running rhythms with τ shorter than 24 h. To identify the genes affecting τ, quantitative trait locus (QTL) analysis was initially conducted by using 289 F2 mice derived from a cross between CS and C57BL/6J strain. A suggestive QTL (LOD = 3.71) with CS allele increasing τ was detected on the distal region of Chromosome (Chr) 19. Next, using 192 F2 mice from a cross between CS and MSM strain, the presence of the QTL on Chr 19 was examined, and we confirmed the QTL at the genome-wide significant level (LOD = 4.61 with 10.4% of the total variance explained). This QTL was named long free-running period (Lfp). Three other suggestive QTLs (LOD = 3.24-4.28) were mapped to the midportion of Chr 12 in (CS×C57BL/6J)F2 mice, and to the proximal and middle region of Chr 19 in (CS×MSM)F2 mice, respectively, of which, CS alleles for two QTLs on Chr 19 have the effect of lengthening τ. None of these QTLs were mapped to the chromosomal regions of previously described QTLs for τ and known clock genes (Clock, mPer1, Bma11, mCry1, mCry2, mTim, and Csnkle).

DOI： 10.1007/s003350010280

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Identification of the suprachiasmatic nucleus in birds

Yoshimura T, Yasuo S, Suzuki Y, Makino E, Yokota Y, Ebihara S

AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY 280 巻 ( 4 ) 頁： R1185 - R1189 2001年4月

Mapping quantitative trait loci for circadian behavioral rhythms in SMXA recombinant inbred strains

Suzuki T, Ishikawa A, Nishimura M, Yoshimura T, Namikawa T, Ebihara S

BEHAVIOR GENETICS 30 巻 ( 6 ) 頁： 447 - 453 2000年11月

記述言語：英語出版者・発行元：Behavior Genetics

SM/J and A/J inbred strain of mice have different characteristics in circadian behaviors such as free-running period (τ), phase relationship (ψ) between light-dark cycles and activity rhythms, and amount of wheel-running activity. To determine the genes which affect these behaviors, a quantitative trait locus (QTL) analysis using SMXA recombinant inbred strains derived from SM/J and A/J mice was performed. Concerning τ, two regions on chromosomes (Chrs) 7 and 18 surpassed the genome-wide suggestive level. As for ψ, one suggestive QTL was detected on Chr 7. The QTLs which affect daily activity counts under light-dark cycles and constant darkness were mapped to the same chromosomal regions on Chrs 1 and 17, respectively. The provisional QTLs detected in the present study might be useful for understanding the complex mechanism regulating circadian behaviors.

DOI： 10.1023/A:1010298701251

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PubMed

Molecular analysis of avian circadian clock genes

Yoshimura T, Suzuki Y, Makino E, Suzuki T, Kuroiwa A, Matsuda Y, Namikawa T, Ebihara S

MOLECULAR BRAIN RESEARCH 78 巻 ( 1-2 ) 頁： 207 - 215 2000年5月

記述言語：英語出版者・発行元：Molecular Brain Research

Unlike mammals, avian circadian rhythms are regulated by a multiple oscillatory system consisting of the retina, the pineal and the suprachiasmatic nucleus in the hypothalamus. To understand avian circadian system, we have cloned Clock and Period homologs (qClock, qPer2 and qPer3) and characterized these genes in Japanese quail. Overall, qCLOCK, qPER2 and qPER3 showed ~79%, ~46% and ~33% amino acid identity to mCLOCK, mPER2, mPER3, respectively. Clock was mapped to quail chromosome 4 and chicken chromosome 4q1.6-q2.1. Per2 and Per3 genes were both localized to microchromosomes. qClock mRNA was expressed throughout the day, while qPer2 and qPer3 showed robust circadian oscillation in the eye and the pineal gland. All three genes were expressed in various tissues. In addition, qPer2 mRNA was induced by light, but neither qClock nor qPer3 was induced. These results can explain the molecular basis for circadian entrainment in Japanese quail and also provide new avenues for molecular understanding of avian circadian clock and photoperiodism. ThemeL Neural basis of behaviour. Topic: Biological rhythms and sleep. Copyright (C) 2000 Elsevier Science B.V.

DOI： 10.1016/S0169-328X(00)00091-7

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