Transcription factor mediation of transcriptome changes and functional remodeling in osmotically stressed hypothalamic n

这个项目背后的驱动力是需要快速利用基因组信息，以获得生理学的理解。我们现在知道哺乳动物大约有30,000个基因。这些数据提出了两个问题，首先，这些基因在哪里和何时表达，其次，这些基因做什么？我们已经解决了这些问题，在一个强大的模型系统，即生理挑战加压素（VP）神经元的下丘脑。当动物脱水时，肽激素VP被释放并通过血流到达位于肾脏中的特定受体靶点，在那里它减少了水的排泄，从而促进了水的保护。这是伴随着大量的变化的形态，电生理特性和生物合成和分泌活动的VP神经元。我们希望了解这种功能的可塑性和它的生理后果方面的差异表达的基因。我们已经使用了微阵列技术，使我们能够在一次检测中观察成千上万个基因的表达。因此，我们编制了目录，代表下丘脑不同区域表达的RNA群体的全面描述。此外，我们已经确定了转录，无论是上调或下调的结果，慢性脱水。我们现在已经选择了5个基因进行进一步的研究，因为它们编码转录因子，这些转录因子是在细胞核中工作以控制基因表达起始的蛋白质，因此共同控制细胞中所有信使RNA的组成。这些基因可能是VP神经元可塑性的重要关键介质或调节因子。为了验证这个假设，我们将：1。使用独立的方法检查数组数据是否正确;2.用一种叫做染色质免疫沉淀的方法找出这些转录因子调节的基因;3.将基因转移到整个生物体中，以确定目标基因产物在控制水平衡中的活性增加或减少的功能后果。这将是第一次基于微阵列输出，在整个动物生理系统的背景下对基因网络进行功能研究。这些数据无疑将有助于更好地了解健康和疾病状态下生理系统可塑性所涉及的基因网络。

The driving force behind this project has been the need to rapidly exploit genomic information in order to obtain physiological understanding. We now know that mammals have approximately 30,000 genes. These data prompt two questions, firstly, where and when are these genes expressed, and secondly, what do these genes do? We have addressed these questions in a robust model system, namely the physiologically challenged vasopressin (VP) neurones of the hypothalamus. When an animal is dehydrated, the peptide hormone VP is released and travels through the blood stream to specific receptor targets located in the kidney, where it reduces the excretion of water, thus promoting water conservation. This is accompanied by a plethora of changes in the morphology, electrophysiological properties and biosynthetic and secretory activity of VP neurones. We wish to understand this functional plasticity and its physiological consequences in terms of the differential expression of genes. We have used microarray techniques that allow us to look at the expression of tens of thousands of genes in a single assay. We have thus compiled catalogues that represent comprehensive descriptions of the RNA populations expressed in different regions of the hypothalamus. Further, we have identified transcripts that are either up- or down-regulated as a consequence of chronic dehydration. We have now selected 5 genes for further study on the basis that they code for transcription factors, proteins that work in the cell nucleus to control the initiation of gene expression, and hence collectively govern the composition of all of the messenger RNAs of a cell. These genes might be important key mediators, or regulators, of VP neuronal plasticity. In order to test this hypothesis, we will:1. check that the array data are correct using independent methods;2. find out which genes these transcription factors regulate using a method called chromatin immunopreciptitation;3. use gene transfer into the whole organism to determine the functional consequences of the increased or decreased activity of target gene products in the control of water balance.This will be the first time that, based on a microarray output, a gene network will be studied functionally in the context of a whole animal physiological system. The data will undoubtedly lead to a better understanding of gene networks involved in the plasticity of a physiological system in health and disease states.