Centromere identity, strength, and regulation

项目概要/摘要 细胞分裂时染色体平均分配的缺陷会导致非整倍性，这是一种遗传灾难， 导致自然流产或出生缺陷，如果它出现在配子，这是一个主要因素， 几乎所有人类癌症的基因剂量失衡。着丝粒是每个染色体上的位点， 在健康细胞的细胞分裂中指导准确的染色体分离，但该领域存在一个悖论 因为通常在基因座上发现的DNA序列对于着丝粒来说既不是必需的，也不是充分的， 功能作为我们对科学的主要贡献领域，迄今为止，我们在过去取得了重大进展， 在阐明着丝粒身份的分子基础方面， 着丝粒染色质的永久性，表观遗传和遗传信息之间的关系，在驱动 真核生物中的着丝粒进化，以及质量控制途径中的关键步骤， 细胞分裂时染色体分离。在未来五年，我们准备在我们的 从三个方面对着丝粒的分子认识。第一个领域是用一种新型的人类人工 染色体（HAC），我们最近开发的。我们将获得新的见解， DNA序列与着丝粒形成之间的关系，拓展了HACs在实验和应用中的应用 设置.第二个领域是用小鼠模型和生化重建来扩展我们的理解 表观遗传学和遗传学在着丝粒上的平衡。我们将在成功的基础上， 哺乳动物中的分子证据表明，进化过程被称为“着丝粒驱动”， 这一过程与着丝粒卫星DNA序列扩增的关系。此外，我们将 研究在人类着丝粒上典型发现的着丝粒重复序列对物理性质的作用， 的着丝粒染色质使用纯化的组件。第三个领域是结合生物物理、细胞 生物学和表观基因组学方法来扩展我们对有丝分裂中着丝粒调控的理解。我们 将集中在“内着丝粒”的染色质上（即在有丝分裂的一对姐妹着丝粒之间）。 染色体），其在称为有丝分裂错误校正的质量控制步骤中起关键作用。总之，我们的 这三个领域的进展将构成我们对分子生物学的理解的重大进展。 着丝粒的特化和调控机制。

Project Summary/Abstract Defects in the equal partitioning of chromosomes at cell division causes aneuploidy, a genetic catastrophe that results in spontaneous abortion or birth defects if it arises in the gametes and that is a major contributor to gene dosage imbalances in almost all human cancers. The centromere is the locus on each chromosome that directs accurate chromosome segregation at cell division in healthy cells, but a paradox exists in the field because the DNA sequences typically found at the loci are neither necessary nor sufficient for centromere function. As our major area of contribution to science, thus far, we have made major headway during the past decade in elucidating the molecular basis for centromere identity, the epigenetic pathway that propagates centromeric chromatin in perpetuity, the relationship between epigenetic and genetic information in driving centromere evolution in eukaryotes, and key steps in the quality control pathway that ensures proper chromosome segregation at cell division. In the next five years, we are poised to make quantum leaps in our molecular understanding of centromeres in three areas. The first area is with a new type of human artificial chromosome (HAC) that we have recently developed. We will gain new insight regarding the relationship between DNA sequence and centromere formation and expand the utility of HACs in experimental and applied settings. The second area is with mouse models and biochemical reconstitution to expand our understanding of the balance of epigenetics and genetics at the centromere. We will build on our success with gaining the first molecular evidence in mammals of an evolutionary process known as “centromere drive” to now define the relationship of this process to the expansion of centromeric satellite DNA sequences. In addition, we will investigate the role of the centromere repeats typically found at human centromeres on the physical properties of centromeric chromatin using purified components. The third area is with a combination of biophysical, cell biological, and epigenomic approaches to extend our understanding of centromere regulation at mitosis. We will focus on the chromatin at the “inner centromere” (i.e. between the pair of sister centromeres on a mitotic chromosome) that plays a key role in the quality control step known as mitotic error correction. Altogether, our progress in these three areas will constitute a major advance in our understanding of the molecular mechanisms underlying the specification and regulation of centromeres.