Mechanisms of condensin-mediated gene regulation in C. elegans

秀丽隐杆线虫凝缩蛋白介导的基因调控机制

• 批准号: 9982361
• 负责人: Sevinc Ercan
• 金额: $ 39.02万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9982361
• 关键词: Address; Affect; Animal Model; Binding; Caenorhabditis elegans; Cell division; Chromosome Condensation; Chromosome Segregation; Chromosome Structures; Chromosomes; Complex; Disease; Dosage Compensation (Genetics); Elements; Eukaryota; Experimental Models; Gene Expression Regulation; Genetic Transcription; Genome; Genomic approach; Genomics; Health; Hermaphroditism; Human; Interphase; Mediating; Molecular; Outcome; Play; Regulation; Regulator Genes; Regulatory Element; Site; Specificity; Structure; Work; X Chromosome; condensin; gene repression; genetic approach; histone modification; imaging approach; protein complex; recruit; transcription factor

PROJECT SUMMARY/ABSTRACT Regulation of chromosome structure is fundamental for genome function. Across eukaryotes, a key regulator of chromosome structure is an evolutionarily conserved protein complex called condensin, which is essential for chromosome condensation and segregation during cell division and play key roles in gene regulation during interphase. The molecular mechanisms behind how condensins bind and regulate chromosome structure and how this affects transcription remain unclear. To address this, we use a specialized condensin that functions within the X chromosome dosage compensation complex (DCC) in C. elegans. DCC specifically binds to and represses transcription of both X chromosomes in hermaphrodites by a factor of two. The co-option of condensin for X chromosome dosage compensation provides a powerful experimental model to study the mechanisms that control specificity of condensin binding and to analyze condensin-mediated changes in chromosome structure and transcription with high precision, all free from potential indirect effects on chromosome segregation. Our previous work suggests that specific and robust DCC binding to the X chromosomes is accomplished by a step-wise recruitment mechanism followed by linear spreading. First, DCC enters the chromosome at a small number of X-specific sites defined by two genomic features: the presence of multiple 12-bp recruitment motifs and overlap with high occupancy transcription factor target sites. After X-specific entry, additional sites cooperate over long-distance to increase the level of DCC recruitment across the chromosome. From the recruitment sites, DCC spreads linearly along large chromosomal domains, accumulating at active gene regulatory elements across the X. DCC binding leads to chromosome-wide transcriptional repression, changes in the level of specific histone modifications, chromosome compaction, and long-range chromosomal interactions. Here, we will address several important questions regarding DCC recruitment, spreading and function using a powerful set of genetic, genomic and imaging approaches: 1) How does the DCC recognize features of the initial entry sites on the X? 2) What is the mechanism behind long-distance cooperation between DCC recruitment elements? 3) How is DCC spreading and DCC-mediated chromosomal interactions regulated? 4) What is the mechanism by which the DCC represses transcription? The outcome of our work will elucidate the basic molecular mechanisms by which condensins perform their wide-range of essential functions in eukaryotes. This is relevant to human health because condensin structure and function is deeply conserved from C. elegans to humans, and determining how condensins function is key to understanding the contribution of chromosome structure to genome function in health and disease.

项目总结/摘要 染色体结构的调节是基因组功能的基础。在真核生物中， 染色体结构是一种进化上保守的蛋白质复合物，称为凝聚素， 染色体在细胞分裂过程中的凝聚和分离，并在基因调控中发挥关键作用， 间期凝聚素如何结合和调节染色体结构以及 这如何影响转录仍不清楚。为了解决这个问题，我们使用一种专门冷凝器， 在C.优雅的DCC特异性结合， 在雌雄同体动物中抑制两条X染色体转录的因子为2。的增选 X染色体剂量补偿的凝聚素为研究X染色体剂量补偿提供了一个强有力的实验模型， 控制凝聚素结合特异性的机制，并分析凝聚素介导的 染色体结构和转录具有高精度，所有这些都没有潜在的间接影响， 染色体分离 我们以前的工作表明，特异性和强大的DCC结合到X染色体是通过一个 逐步招募机制，然后是线性扩散。首先，DCC以很小的速率进入染色体。 由两个基因组特征定义的X特异性位点的数量：存在多个12 bp募集基序 并与高占有率的转录因子靶位点重叠。在X特定条目之后，其他站点 通过长距离合作来增加染色体上DCC募集的水平。从 募集位点，DCC沿着大的染色体结构域线性扩散，在活性基因处积累 整个X的调节元件。DCC结合导致染色体范围的转录抑制， 在特定组蛋白修饰、染色体致密化和长距离染色体 交互.在这里，我们将解决有关DCC招聘，传播和 使用一组强大的遗传学、基因组学和成像方法功能：1）DCC如何识别 在X上的初始入口网站的功能？2)远程合作背后的机制是什么 DCC招募人员之间的联系3)DCC如何传播和DCC介导的染色体相互作用 监管？4)DCC抑制转录的机制是什么？ 我们的工作结果将阐明凝聚素发挥其功能的基本分子机制。 在真核生物中广泛的基本功能。这与人类健康有关，因为冷凝结构 并且功能与C.而确定凝聚素的功能是关键 了解染色体结构对健康和疾病中基因组功能的贡献。