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: 10629234
• 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/10629234
• 关键词: Address; Affect; 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; feature detection; gene repression; genetic approach; histone modification; imaging approach; model organism; 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.

项目摘要/摘要 染色体结构的调节对于基因组功能至关重要。跨真核生物，一个关键的调节器 染色体结构是一种称为冷凝蛋白的进化保守的蛋白质复合物，这对于 细胞分裂期间的染色体凝结和隔离，并在基因调节中起关键作用 相间。冷凝蛋白如何结合和调节染色体结构的分子机制和 这如何影响转录仍不清楚。为了解决这个问题，我们使用功能的专业冷凝蛋白 在秀丽隐杆线虫中的X染色体剂量补偿复合物（DCC）中。 DCC专门结合并 抑制两个X染色体在Hermaphrodites中的转录倍数。共同选择 X染色体剂量补偿的冷凝蛋白提供了一个强大的实验模型来研究 控制冷凝蛋白结合并分析冷凝蛋白介导的变化的机制 染色体结构和高精度的转录，全部没有潜在的间接影响 染色体分离。 我们以前的工作表明，特定而鲁棒的DCC与X染色体结合是由A实现的 逐步招募机制，然后是线性扩散。首先，DCC进入一个小的染色体 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 并与高占用转录因子目标位点重叠。特定于X的进入后，其他站点 长途合作，以提高整个染色体的DCC招募水平。来自 DCC招募部位沿大型染色体结构域线性扩散，积累在活性基因 X. DCC结合的调节元素会导致全染色体的转录抑制，变化 在特定组蛋白修饰的水平中，染色体压实和远距离染色体 互动。在这里，我们将解决有关DCC招聘，传播和的几个重要问题 使用强大的遗传，基因组和成像方法的功能：1）DCC如何识别 X上初始输入站点的功能？ 2）长途合作背后的机制是什么 在DCC招聘元素之间？ 3）如何扩散DCC和DCC介导的染色体相互作用 受监管？ 4）DCC抑制转录的机制是什么？ 我们工作的结果将阐明冷凝蛋白执行其基本分子机制 真核生物中的重要功能。这与人类健康有关，因为冷凝蛋白结构 功能从秀丽隐杆线虫到人类深处，并确定冷凝蛋白的功能是关键 了解染色体结构对健康和疾病中基因组功能的贡献。