Mechanisms of Transient Transcription in Yeast

酵母瞬时转录机制

基本信息

批准号：
8725021
负责人：
RANDY S STRICH
金额：
$ 15.69万
依托单位：
ROWAN UNIVERSITY SCHOOL/OSTEOPATHIC MED
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-09-01 至 2014-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8725021
关键词：
Mechanisms Transient Transcription Yeast

项目摘要

DESCRIPTION (provided by applicant): The spatial and temporal expression of specific gene sets is critical for the execution of complex differentiation programs. The long-term goal of this study is to mechanistically define transient transcription in the context of the budding yeast meiotic differentiation program. Many genes required for the meiotic landmark events are repressed during mitotic cell division but then transiently induced during development in temporal waves termed "early", "middle" and "late". Ume6p binds "early" meiotic gene promoters and mediates their vegetative repression by recruiting both histone deacetylase (HDAC) and chromatin remodeling complexes. We have recently discovered that early meiotic gene induction requires Ume6p destruction by the Cdc20p- directed anaphase promoting complex/cyclosome (APC/C) ubiquitin ligase. Although well known for its role in controlling the G2 -> M transition in mitotic cells, this is the first report that APC/CCdc20 targets a transcription factor for destruction. In addition, Ume6p destruction is restricted to cells entering meiosis, even though APC/CCdc20 is active (and Ume6p is present) during mitotic cell division. The meiotic inducer Ime1p provides a trigger to promote Ume6p destruction thus suggesting a new mechanism by which APC/C substrate selection is redirected within the context of a differentiation program. While searching for potential meiosis-specific destruction signals, we discovered that Ume6p is a substrate of the Gcn5p histone acetyltransferase (HAT) complex called SAGA. The well-studied acetylation and deacetylation of nucleosomes maintains chromatin in "open" and "closed" configurations, respectively. However, the acetylation of transcription factors has not been demonstrated previously in yeast and has only been described for a few transactivators in mammalian systems. To our knowledge, Ume6p is the first transcriptional repressor found to be acetylated. Interestingly, preliminary results point to a role for acetylation in both preventing Ume6p DNA binding ability and enhancing its degradation. These findings suggest a new model for Gcn5p-dependent transcriptional activation through direct inhibition of Ume6p repressor function. Following induction, meiotic gene expression and the execution of landmark events are coupled by a series of checkpoint systems. Preliminary results indicate that Ume6p destruction is prevented upon activation of the DNA damage checkpoint. The mechanism by which Ume6p is protected from destruction following checkpoint activation, or the role of additional checkpoint pathways, is unknown. To understand the molecular mechanisms by which Ume6p-dependent repression is relieved upon meiotic induction, and how repression is reestablished in response to checkpoint pathways, the following aims are proposed: Aim1. Dissect the molecular mechanisms directing developmental re-tasking of the APC/C. Aim2. Determine the role that acetylation plays in Ume6p activity and regulation. Aim3. Identify and characterize the meiotic pathways that mediate Ume6p destruction.

描述（由申请人提供）：特定基因集的空间和时间表达对于执行复杂的分化程序至关重要。这项研究的长期目标是在萌芽的酵母减少分化计划的背景下机械地定义瞬态转录。减数分裂地标的事件所需的许多基因在有丝分裂细胞分裂期间受到抑制，但随后在发育过程中暂时诱导了称为“早期”，“中间”和“晚期”的颞波。 UME6P结合“早期”减数分裂基因启动子，并通过募集组蛋白脱乙酰基酶（HDAC）和染色质重塑复合物来介导其营养抑制。我们最近发现，早期的减数分裂基因诱导需要CDC20P定向的后期促进复合物/循环体（APC/C）泛素连接酶的UME6P破坏。尽管以控制有丝分裂细胞的G2-> M跃迁而闻名，但这是APC/CCDC20靶向破坏的转录因子的第一项报告。此外，即使在有丝分裂细胞分裂过程中APC/CCDC20在活性（并且存在UME6P），UME6P的破坏仅限于进入减数分裂的细胞。减数分裂诱导剂IME1P提供了一种触发促进UME6P破坏的触发因素，因此提出了一种新机制，通过该机制，APC/C基板在差异化程序的背景下重定向。在寻找潜在的减数分裂特异性破坏信号时，我们发现UME6P是GCN5P组蛋白乙酰基转移酶（HAT）复合物的底物，称为SAGA。核小体的精心研究的乙酰化和脱乙酰化分别保持了“开放”和“封闭”构型的染色质。但是，转录因子的乙酰化先前尚未在酵母中证明，并且仅针对哺乳动物系统中的一些反式激活剂进行了描述。据我们所知，UME6P是发现乙酰化的第一个转录阻遏物。有趣的是，初步结果表明乙酰化在防止UME6P DNA结合能力和增强其降解中的作用。这些发现提出了一种通过直接抑制UME6P抑制器函数来依赖GCN5P转录激活的新模型。诱导后，一系列检查点系统将减数分裂基因的表达和地标事件的执行。初步结果表明，激活DNA损伤检查点后阻止UME6P破坏。在检查点激活后，保护UME6P免受破坏或其他检查点途径的作用的机制尚不清楚。为了了解减数分裂诱导的分子机制，以及如何响应检查点途径来缓解减数分裂诱导的抑制作用，并提出了以下目的：AIM1。解剖指导APC/C的发育重新任务的分子机制。 AIM2。确定乙酰化在UME6P活性和调节中起作用的作用。 AIM3。识别并表征介导UME6P破坏的减数分裂途径。

项目成果

期刊论文数量（5）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Meiotic, cryptic, and stable unannotated transcripts: noncoding RNAs add to the epigenetic tool box controlling meiotic development.

减数分裂、神秘且稳定的未注释转录本：非编码 RNA 添加到控制减数分裂发育的表观遗传工具箱中。

DOI：
10.1073/pnas.1018013108
发表时间：
2011
期刊：
Proceedings of the National Academy of Sciences of the United States of America
影响因子：
11.1
作者：
Strich,Randy
通讯作者：
Strich,Randy

Rpl22 is required for IME1 mRNA translation and meiotic induction in S. cerevisiae.

Rpl22 是酿酒酵母 IME1 mRNA 翻译和减数分裂诱导所必需的。