Centromere identity, strength, and regulation

项目摘要/摘要 细胞分裂时染色体平均分割的缺陷会导致非整倍体，这是一种遗传灾难， 如果它出现在配子中，会导致自然流产或出生缺陷，这是导致 几乎所有人类癌症中的基因剂量不平衡。着丝粒是每条染色体上的位置 在健康细胞的细胞分裂中，染色体的准确分离是正确的，但这一领域存在一个悖论。 因为通常在基因座上发现的DNA序列对着丝粒来说既不必要也不充分 功能。作为我们对科学作出贡献的主要领域，到目前为止，我们在过去取得了重大进展 十年来阐明着丝粒特性的分子基础，即传播的表观遗传途径 着丝粒染色质的永久性，驾驶过程中表观遗传和遗传信息的关系 真核生物的着丝粒进化，以及确保适当的质量控制途径的关键步骤 细胞分裂时的染色体分离。在接下来的五年里，我们准备在我们的 三个区域着丝粒的分子理解。第一个领域是用一种新型的人类人工 染色体(HAC)，这是我们最近开发的。我们将对两国关系有新的认识 DNA序列与着丝粒形成的关系及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大我们的理解 着丝粒的表观遗传学和遗传学的平衡。我们将在成功的基础上取得第一 哺乳动物的分子证据表明了一种称为着丝粒驱动的进化过程，这种进化过程现在定义了 这一过程与着丝粒卫星DNA序列的扩展之间的关系。此外，我们还将 研究人类着丝粒上常见的着丝粒重复序列在物理特性上的作用 使用纯化组分的着丝粒染色质。第三个领域是生物物理、细胞 生物学和表观基因组学方法，以扩展我们对着丝粒调控在有丝分裂中的理解。我们 将集中在“内着丝粒”处的染色质(即有丝分裂上的姐妹着丝粒之间 染色体)，在称为有丝分裂纠错的质量控制步骤中起着关键作用。总之，我们的 这三个领域的进展将构成我们对分子的理解的重大进步 着丝粒的规范和调控的基本机制。

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.