Regulation of Chromosome Segregation in Human Cells

人体细胞染色体分离的调控

• 批准号: 7247247
• 负责人: Prasad V Jallepalli
• 金额: $ 33.96万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7247247
• 关键词: Regulation; Chromosome; Segregation; Human; Cells

DESCRIPTION (provided by applicant): Chromosome segregation is crucial to the health and survival of all organisms. Accumulating evidence indicates that the vast majority of human cancers display high rates of chromosome missegregation. This phenomenon, termed chromosomal instability (CIN), has been proposed to drive tumorigenesis by facilitating the emergence of aneuploid clones with increased malignant potential. Thus, it is imperative to obtain a better understanding of the molecules and mechanisms that regulate the process of chromosome segregation in human cells and sustain its high fidelity. We have developed novel methods for 'knocking out' genes in human somatic cells, and we have used these methods to characterize the role of a small mitosis-regulating protein termed securin. This protein forms a tight complex with a large cysteine protease termed separase, which digests the physical links that hold sister chromatids together. Based on our preliminary studies, we hypothesize that the securin-separase complex plays a central role in mitotic progression and high-fidelity chromosome segregation in humans. Precise regulation of this complex is proposed to link sister chromatid separation to upstream checkpoints and restrict it to the the appropriate phase of the cell cycle, i.e., anaphase. To test these hypotheses, we will investigate how specific post-translational modifications contribute to the function of the separase-securin complex. In Aim 1, we use a genetic approach to elucidate the in vivo role of separase auto-cleavage, to determine its relevance to mitotic progression and chromosome dynamics. In Aim 2, we test a proposed securin-independent mechanism for inhibiting premature sister chromatid separation, taking advantage of the hSecurin- 'knockout' cells developed in our earlier studies. In Aim 3, we evaluate potential mechanisms for separase-dependent regulation of processes other than sister chromatid separation. Together, these studies will significantly advance our understanding of mitotic chromosome segregation in humans. Such information is essential to developing more effective cancer therapies that attack the CIN phenotype found in most cancer cells.

描述（由申请人提供）：染色体分离对所有生物体的健康和生存至关重要。越来越多的证据表明，绝大多数人类癌症显示出高比率的染色体错误分离。这种现象，称为染色体不稳定性（CIN），已被提出通过促进具有增加的恶性潜能的非整倍体克隆的出现来驱动肿瘤发生。因此，必须更好地了解调节人类细胞染色体分离过程并维持其高保真度的分子和机制。 我们已经开发出了新的方法来“敲除”人体细胞中的基因，我们已经使用这些方法来表征一个小的有丝分裂调节蛋白securin的作用。这种蛋白质与一种称为分离酶的大的半胱氨酸蛋白酶形成紧密的复合物，分离酶破坏了将姐妹染色单体保持在一起的物理连接。基于我们的初步研究，我们假设securin-separase复合物在人类有丝分裂进程和高保真染色体分离中起着核心作用。该复合物的精确调节被提议将姐妹染色单体分离与上游检查点联系起来，并将其限制在细胞周期的适当阶段，即，后期为了验证这些假设，我们将研究特定的翻译后修饰如何有助于分离酶-安全蛋白复合物的功能。在目的1中，我们使用遗传学方法来阐明分离酶自动切割的体内作用，以确定其与有丝分裂进程和染色体动力学的相关性。在目标2中，我们测试了一个建议的securin独立的机制，抑制过早的姐妹染色单体分离，利用我们早期的研究中开发的hSecurin '敲除'细胞。在目标3中，我们评估了除姐妹染色单体分离之外的分离酶依赖性过程调节的潜在机制。总之，这些研究将大大推进我们对人类有丝分裂染色体分离的理解。这些信息对于开发更有效的癌症疗法，攻击大多数癌细胞中发现的CIN表型至关重要。