Transcriptional Regulation by Chromatin Modifiers

染色质修饰剂的转录调控

• 批准号: 6760038
• 负责人: YOSHIHIRO NAKATANI
• 金额: $ 35.91万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6760038
• 关键词: DNA binding protein; DNA directed RNA polymerase; DNA replication; HeLa cells; antibody; chromatin; dimer; gel filtration chromatography; gene induction /repression; genetic transcription; histones; immunoprecipitation; mass spectrometry; methylation

DESCRIPTION (provided by applicant): Transcription is temporally and spatially regulated via changes in chromatin structure. Gene regulation via formation of transcriptionally active or inactive chromatin is stable' d to be a cellular memory system that is responsible for the inheritance of gene activity to progeny cells. In quiescent cells, these mechanisms appear to be involved in stable long-term repression of a variety of genes, which are responsible for cell proliferation. Indeed, such sealing of "unnecessary" genes is crucial for maintaining the quiescent state. Accordingly, any defect in such silencing mechanisms results in the expression of "unnecessary" genes in quiescent cells, leading to tumorigenesis. While many factors that are responsible for silencing have been identified by genetic screening, mechanisms by which they contribute to the formation of inactive chromatin remain largely unclear. To explore these mechanisms, we have purified a key protein complex that plays important roles in the formation of inactive chromatin in quiescent cells. Further characterization of this complex will provide new insights into mechanisms by which normal cells maintain the quiescent state, and further, by which transcription is perturbed in tumor cells. Moreover, we will investigate how the patterns of transcriptional activity are transmitted to progeny cells. Several lines of evidence suggest that histone H2AZ, a major histone variant that occupies 5% to 10% of total H2A, is deposited onto transcriptionally active chromatin. To reveal mechanisms by which histone H2AZ is incorporated into active chromatin and contribute to gene activation, we have purified at least two H2AZ-containing complexes. Functional analyses of these complexes will solve, at least in part, the puzzle of how histone H2AZ exerts its specific and diverse effects to transmit the patterns of transcriptionally active chromatin to progeny cells.

描述（由申请人提供）：转录通过染色质结构的变化在时间和空间上进行调节。通过形成转录活性或非活性染色质进行的基因调控是稳定的细胞记忆系统，负责将基因活性遗传给子代细胞。在静止细胞中，这些机制似乎涉及多种基因的稳定长期抑制，这些基因负责细胞增殖。事实上，这种“不必要”基因的封闭对于维持静止状态至关重要。因此，这种沉默机制的任何缺陷都会导致静止细胞中“不必要”的基因表达，从而导致肿瘤发生。虽然通过基因筛查已经鉴定出许多导致沉默的因素，但它们导致失活染色质形成的机制仍不清楚。为了探索这些机制，我们纯化了一种关键的蛋白质复合物，该复合物在静止细胞中失活染色质的形成中发挥重要作用。该复合物的进一步表征将为正常细胞维持静止状态的机制以及肿瘤细胞中转录受到干扰的机制提供新的见解。 此外，我们将研究转录活性模式如何传递给后代细胞。多项证据表明，组蛋白 H2AZ（占总 H2A 5% 至 10% 的主要组蛋白变体）沉积在转录活性染色质上。为了揭示组蛋白 H2AZ 掺入活性染色质并促进基因激活的机制，我们纯化了至少两种含有 H2AZ 的复合物。这些复合物的功能分析将至少部分地解决组蛋白 H2AZ 如何发挥其特定和多样化的作用，将转录活性染色质的模式传递给后代细胞的难题。