Regulation of nitrogen catabolic gene expression

描述(由申请人提供)： 酿酒酵母中的氮代谢是一个很好的模型系统。 用来研究真核转录调控和调控网络。 这种酵母能够选择性地优先利用好的氮源。 为可怜的人干杯。这种选择性(指定为氮分解代谢抑制，NCR) 是通过四个GATA转录因子的调节操作完成的 (Gln3p、Gat1p/Nil1p、Dal80p/UGa43p、Deh1p/GZF3p)与包含GATA的 NCR敏感基因启动子的序列。汇总来自以下几个项目的工作 实验室，包括我们自己的，已经表明当氮过多时， Gln3p和Gat1p被磷酸化，并被排除在细胞核之外。当氮气 是有限的，这些蛋白质不再被磷酸化，变成局部化 细胞核，并介导NCR敏感的转录。我们建议继续 我们对GATA家族调节子的研究，进行的实验将 阐明Gln3p、Gat1p和Gat1p调控的步骤和蛋白 Ure2p活性和细胞内定位。我们还将调查 Mks1p影响GATA调节子运行的机制。我们有 在我们实验室建立了全基因组转录分析，并建议 识别：新成员的GATA因子调节子，成员的方式 基因是受调控的，以及它们如何反过来调控GATA-因子基因的表达 和活动。发现了三个新的GATA因子：Gat2p、Gat3p和Gat4p 在我们的试点实验中。我们建议确定Gat2p的功能，即 是与Gat1p结构上同源性最高的GATA因子。我们还将 确定Gat2p本身是如何监管的。我们特别感兴趣的是 GATA因子调节子组分与其他组分的接口和整合 细胞内的调控系统。即使是这个简单系统的复杂性也是 令人望而生畏，但将为 发展和解释更复杂的酵母和哺乳动物的研究 监管层出不穷。

DESCRIPTION (provided by applicant): Nitrogen metabolism in the yeast S. cerevisiae is an excellent model system in which to study eucaryotic transcriptional regulation and regulatory networks. This yeast is able to selectively utilize good nitrogen sources in preference to poor ones. This selectivity (designated nitrogen catabolite repression, NCR) is accomplished through regulated operation of four GATA-transcription factors (Gln3p, Gat1p/Nil1p, Dal80p/Uga43p, Deh1p/ GZF3p) that bind to GATA-containing sequences in the promoters of NCR-sensitive genes. Aggregate work from several laboratories, including our own, has shown that when nitrogen is in excess, Gln3p and Gat1p are phosphorylated and excluded from the nucleus. When nitrogen is limiting, these proteins are no longer phosphorylated, become localized to the nucleus, and mediate NCR-sensitive transcription. We propose to continue our studies of the GATA-family regulon, performing experiments that will elucidate the steps and proteins involved in the regulation of Gln3p, Gat1p and Ure2p activities and intracellular localization. We will also investigate the mechanisms by which Mks1p influences operation of the GATA regulon. We have established genome-wide transcription analysis in our lab and propose to identify: new members of the GATA-factor regulon, the ways in which the member genes are regulated, and how they in turn regulate GATA-factor gene expression and activity. Three new GATA-factors, Gat2p, Gat3p and Gat4p, were discovered in our pilot experiment. We propose to identify the functions of Gat2p, which is the GATA-factor most structurally homologous to Gat1p. We will also determine how Gat2p itself is regulated. We are especially interested in the interface between and integration of GATA-factor regulon components with other regulatory systems in the cell. The complexity of even this simple system is daunting, but will yield highly useful information and experience for developing and interpreting studies of far more complicated yeast and mammalian regulatory cascades.