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Mechanisms of circadian rhythm analyzed from transcription factor of mRNA in suprachiasmatic nucleus

从视交叉上核mRNA转录因子分析昼夜节律机制

基本信息

批准号：
08670086
负责人：
ISOBE Yoshiaki
金额：
$ 1.47万
依托单位：
Nagoya City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08670086/
关键词：
Suprachiasmatic nuclei Arg-vasopressin transcription GABA c-fos AP-1 RT-PCR プロモーター Clock 転写 IEG

项目摘要

Mammalian circadian rhythm is regulated by a pacemaker in the suprachiasmatic nuclei (SCN) of hypothalamus. The SCN containing variety of peptides. Argvasopressin (AVP) containing neuron is one of the output neuron of circadian signal from the SCN to the other brain area. For the entraining mechanism of pacemaker, vasoactive intestinal peptide (VIP), gastrin-releasing peptide are considered to be concerned. While the function of these peptides on the AVP release is reciprocal ; i.e.we found that the VIP increased AVP release, while gastrin-releasing peptide decreased AVP release. Many SCN-specific mRNA from are found by using differential display PCR throughout a day. However, a few products appeared only at CT 20-23. AVP peptide in SCN is higher in subjective day than in night. The qualitative assay of AVPmRNA in SCN is desired to be analyzed in individual animals to compare the peptide levels and other circadian index. We could detect the AVPmRNA levels extracted from two punches of SCN in one rat by using RT-PCR with specific primers. The pattern of day-night variations in PCR product-intensity are similar with that analyzed by Northern blot. These day-night variations were free-run until 21st day under the constant dim light. We find the differential responses in SCN (parvocellular AVP containing neuron) and supraoptic nucleus (magunocellular) against to GABA and corticosterone/dexamethasone. Photic atimulation from retina induces c-fos development in SCN.c-fos development couples with the phase responses and other indexes of circadian rhythm. It is reasonable to speculate that the AVP coding gene might containing IEG (c-fos) binding site at the upstream of 5' promoter area. Although, the AVP coding DNA has no AP-1 binding site that was sequenced from the genome obtained from supraoptic nucleus or other brain area. We are searching the specific genome which code AVPmRNA originating from the SCN.

哺乳动物的昼夜节律是由下丘脑视交叉上核（SCN）中的起搏点调节的。SCN含有多种多肽。精氨酸加压素（Argvasopressin，AVP）神经元是SCN向其他脑区输出昼夜节律信号的神经元之一。对于起搏器的转运机制，血管活性肠肽（VIP）、胃泌素释放肽（GRP）被认为是值得关注的。而这些肽对AVP释放的作用是相互的，即我们发现VIP增加AVP释放，而胃泌素释放肽减少AVP释放。通过使用差异显示PCR在一天中发现许多SCN特异性mRNA。然而，少数产品仅在CT 20-23出现。SCN中AVP肽在主观上白天高于夜间。SCN中AVPmRNA的定性测定需要在个体动物中进行分析，以比较肽水平和其他昼夜节律指数。用特异性引物进行RT-PCR，可检测到大鼠SCN两次穿孔中AVPmRNA的表达。PCR产物强度的昼夜变化规律与北方杂交结果相似。这些昼夜变化是自由运行，直到第21天下恒定的昏暗的光。我们发现SCN（含AVP的小细胞神经元）和视上核（大细胞）对GABA和皮质酮/地塞米松的反应不同。视网膜光刺激诱导SCN中c-fos的发育，c-fos的发育与相位反应和其他昼夜节律指标相耦合。推测AVP编码基因可能在5'端启动子区上游含有IEG（c-fos）结合位点。然而，AVP编码DNA不具有从视上核或其他脑区域获得的基因组测序的AP-1结合位点。我们正在寻找编码来源于SCN的AVPmRNA的特定基因组。