Chromatin and Transcriptional Regulation of CHA1 in Yeast

酵母中 CHA1 的染色质和转录调控

• 批准号: 0517825
• 负责人: Randall Morse
• 金额: --
• 依托单位: Health Research Incorporated/New York State Department of Health
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0517825&HistoricalAwards=false
• 关键词: Chromatin; Transcriptional; Regulation; CHA1; Yeast

The long term goal of this project is to gain new understanding into mechanisms of chromatin-mediated gene regulation. DNA in higher organisms, including humans, is packaged into nucleosomes by wrapping around an octamer of histone proteins. This creates a potential impediment to protein-DNA interactions needed for transcription of DNA into RNA, and so at many genes these nucleosomes must be remodeled to allow transcription to occur. Enzymes and pathways that allow chromatin remodeling have been identified for some genes, but for many others these pathways remain unknown. To gain new insight into regulation of transcription by chromatin, this work will focus on the Saccharomyces cerevisiae CHA1 gene. The CHA1 promoter is readily inducible by addition of serine to growth medium, and its chromatin is remodeled upon activation. Genetic and biochemical approaches will be used to ascertain the mechanism by which CHA1 chromatin structure is remodeled during activation. Repression of CHA1 in the absence of inducing signal will also be investigated. It was shown that loss of the histone H3 amino terminus causes strong CHA1 transcription under uninduced conditions, accompanied by chromatin remodeling. Novel histone H3 mutations that cause CHA1 derepression have been isolated, and will be used in a suppressor screen to uncover genes contributing to histone-mediated CHA1 repression. The significance of this work lies in its investigation of basic mechanisms of chromatin-mediated gene regulation. Chromatin has been implicated in gene regulation in development and in hormone regulation, and so is of fundamental importance. Since remodeling of the CHA1 gene does not use known mechanisms of chromatin remodeling, these studies are expected to yield fundamental new insight into this aspect of gene regulation. Furthermore, since the proteins involved in gene regulation and in chromatin are highly conserved between yeast and higher eukaryotes, including humans, these studies will reveal aspects of regulation that are likely to be common across the eukaryotic kingdom.

该项目的长期目标是对染色质介导的基因调节的机制有了新的了解。包括人类在内的较高生物体中的DNA通过包裹组蛋白的八聚体来包装到核小体中。 这会产生对DNA转录到RNA所需的蛋白-DNA相互作用的潜在障碍，因此在许多基因上，必须重塑这些核小体以允许进行转录。 已经确定了某些基因的酶和允许染色质重塑的酶和途径，但是对于许多其他基因而言，这些途径仍然未知。 为了获得对染色质调节转录的新见解，这项工作将集中于酿酒酵母CHA1基因。 通过将丝氨酸添加到生长培养基中，CHA1启动子很容易诱导，并且激活后其染色质被重塑。 遗传和生化方法将用于确定在激活过程中重塑CHA1染色质结构的机制。在没有诱导信号的情况下，CHA1的抑制也将被研究。 结果表明，在未诱导的条件下，组蛋白H3氨基末端的损失会导致强大的CHA1转录，并伴有染色质重塑。 引起CHA1压缩的新型组蛋白H3突变已被分离，并将用于抑制筛选中，以发现有助于组蛋白介导的CHA1抑制的基因。 这项工作的意义在于其研究染色质介导的基因调节的基本机制。 染色质与基因调节有关在发育和激素调节中，这至关重要。 由于CHA1基因的重塑不使用染色质重塑的已知机制，因此预期这些研究将对基因调节的这一方面产生基本的新见解。 此外，由于涉及基因调节和染色质中的蛋白质在包括人类在内的酵母菌和更高的真核生物之间是高度保守的，因此这些研究将揭示调节的各个方面，这些方面可能在整个真核生物界很常见。