SAS GENE FUNCTIONS AND CHROMATIN AND SILENCING

SAS 基因功能以及染色质和沉默

• 批准号: 6386755
• 负责人: LORRAINE PILLUS
• 金额: $ 20.67万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6386755
• 关键词: Saccharomyces; acetylation; acute myelogenous leukemia; acyltransferase; chromatin; enzyme activity; fungal genetics; gene induction /repression; gene mutation; genetic transcription; human genetic material tag; molecular genetics; yeast two hybrid system

The proposed project's goals are to understand the function of the newly identified SAS gene family in chromatin-mediated transcriptional regulation and genomic silencing. A sequence signature shared by Sas proteins and enzymes known to have acetyltransferase activity suggests that the Sas proteins function by acetylating key chromatin components. SAS genes were discovered in the yeast Saccharomyces, but sequence homologs including human MOZ and Tip60, have significant implications for human health. MOZ is the common 5' partner in recurrent 8p11 translocations that lead to the M4/M5 subtype of acute myeloid leukemia. Tip60 is a human gene associated with HIV-Tat that facilitates increased levels of Tat-dependent transcription. Understanding the most conserved elements of SAS function may thus lead to increased understanding of leukemia and HIV related disease including AIDS and AIDS-related malignancies. Analysis of yeast SAS function revealed that SAS2 or SAS3 mutants are defective in transcriptional silencing. The third yeast gene, ESA1, is essential for viability. Because ESA1 is most closely related to the human homologs, much of the proposal focuses on its analysis. Conditional alleles, including mutations in the putative acetyltransferase domain, will identify critical regions of ESA 1. Analysis of conditional alleles will facilitate the proposed genetic and cell biological dissection of ESA 1. It will be determined if ESA 1 is required at a single or multiple points in the cell cycle and if loss of ESA1 function leads to silencing defects, thereby potentially identifying genetic loci whose repression is essential for normal mitotic growth. Biochemical characterization will test directly the hypothesis that SAS genes function through chromatin acetylation. Identification of relevant substrates and regulators of activity will be sought through biochemical and genetic approaches. Tests to determine limits of functional conservation between yeast and human SAS genes will be performed by determining if human genes can suppress yeast mutant phenotypes. Experiments will be performed to test the hypothesis that mis-localization of SAS activity may lead to disease by altering locally defined patterns of transcriptional regulation. Results from these diverse experimental approaches should establish mechanisms of SAS gene function and suggest how disruption of this function leads to alterations in genomic silencing and activation.

拟议项目的目标是了解 新发现的染色质介导转录中的 SAS 基因家族 调控和基因组沉默。 Sas 共享的序列签名 已知具有乙酰转移酶活性的蛋白质和酶表明 Sas 蛋白通过乙酰化关键染色质成分发挥作用。 在酵母菌中发现了 SAS 基因，但序列 包括人类 MOZ 和 Tip60 在内的同源物具有重大意义 为了人类的健康。 MOZ 是循环 8p11 中常见的 5' 伙伴 导致急性髓系细胞 M4/M5 亚型的易位 白血病。 Tip60 是一种与 HIV-Tat 相关的人类基因 促进 Tat 依赖性转录水平的提高。 了解 SAS 功能中最保守的元素可能会导致 增进对白血病和艾滋病毒相关疾病的了解 包括艾滋病和与艾滋病相关的恶性肿瘤。酵母 SAS 分析 功能显示 SAS2 或 SAS3 突变体有缺陷 转录沉默。第三个酵母基因 ESA1 对于 生存能力。因为 ESA1 与人类同源物关系最为密切， 该提案的大部分内容侧重于其分析。条件等位基因， 包括假定的乙酰转移酶结构域中的突变，将 识别 ESA 的关键区域 1. 条件等位基因分析 将促进拟议的遗传和细胞生物学解剖 ESA 1。将确定是否需要 ESA 1 在单一或 细胞周期中的多个点以及 ESA1 功能丧失是否导致 沉默缺陷，从而有可能识别遗传位点 其抑制对于正常有丝分裂生长至关重要。生化 表征将直接检验 SAS 基因的假设 通过染色质乙酰化发挥作用。相关鉴定 活性底物和调节剂将通过以下方式寻找 生物化学和遗传学方法。确定极限的测试 酵母和人类 SAS 基因之间的功能保守性将 通过确定人类基因是否可以抑制酵母突变体来进行 表型。将进行实验来检验以下假设： SAS 活性的错误定位可能会通过改变 局部定义的转录调控模式。 结果来自 这些不同的实验方法应该建立机制 SAS 基因功能并表明该功能的破坏如何导致 基因组沉默和激活的改变。