Roles of chromosomal factors in chromosome segregation

染色体因素在染色体分离中的作用

• 批准号: 6964186
• 负责人: Hironori Funabiki
• 金额: $ 32.11万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6964186
• 关键词: SDS polyacrylamide gel electrophoresis; Xenopus oocyte; binding proteins; cell cycle; chromosome movement; enzyme activity; mass spectrometry; microtubules; mitotic spindle apparatus; phosphotransferases; polymerase chain reaction; tubulin

DESCRIPTION (provided by applicant): Chromosomes must be equally segregated during cell division. Eukaryotes use microtubules to control the positioning and movement of chromosomes. In addition to kinetochores and centrosomes, the chromatin that makes up the chromosome arms plays important roles in organizing spindle microtubules. The long-term goal of this proposal is to understand how chromosomal factors influence the local environment and coordinate chromosome segregation. To approach this goal, we used expression screening to identify new metaphase chromosome-binding proteins, and discovered Dasra A and Dasra B, two new components of the vertebrate chromosomal passenger complex, which contains the kinase Aurora B. This complex plays roles in the spindle checkpoint and cytokinesis, and it has been proposed to regulate microtubule dynamics. Whereas Dasra B is conserved among vertebrates, Dasra A homologs can be found in fishes, frogs and chicken, but not in mammals. One of the characteristics distinguishing Dasra A-containing vertebrates from mammals is the rapid early embryonic cell divisions during which the checkpoint controls are suppressed, suggesting that Dasra A may be specialized to regulate spindle assembly in these rapid cell division cycles. Using Xenopus egg extracts, we propose to: 1) Determine the full constituents of the chromosomal passenger complex. 2) Distinguish the functions of Dasra A and Dasra B in chromatin-induced spindle assembly, in activation/maintenance of the spindle assembly checkpoint, and in the regulation of the kinase activity of Aurora B. 3) Examine how the chromosomal passenger complex is regulated on chromosomes. Do chromosomes biochemically activate the chromosomal passenger complex, or are chromosomes simply used for increasing local concentration of the complex? The findings of this proposal will help us understand how normal cells segregate their chromosomes accurately and how this process fails in cancer cells and in birth defects.

描述（由申请人提供）：细胞分裂过程中染色体必须均匀分离。真核生物利用微管来控制染色体的定位和运动。除了着丝粒和中心体之外，构成染色体臂的染色质在组织纺锤体微管中也发挥着重要作用。该提案的长期目标是了解染色体因素如何影响局部环境并协调染色体分离。为了实现这一目标，我们使用表达筛选来鉴定新的中期染色体结合蛋白，并发现了 Dasra A 和 Dasra B，它们是脊椎动物染色体过客复合物的两个新成分，其中含有激酶 Aurora B。该复合物在纺锤体中发挥作用检查点和胞质分裂，并且已被提议调节微管动力学。 Dasra B 在脊椎动物中保守，而 Dasra A 同源物可以在鱼类、青蛙和鸡中找到，但不能在哺乳动物中找到。含有 Dasra A 的脊椎动物与哺乳动物的区别特征之一是快速的早期胚胎细胞分裂，在此期间检查点控制受到抑制，这表明 Dasra A 可能专门调节这些快速细胞分裂周期中的纺锤体组装。使用非洲爪蟾卵提取物，我们建议：1) 确定染色体乘客复合物的全部成分。 2) 区分 Dasra A 和 Dasra B 在染色质诱导纺锤体组装、纺锤体组装检查点激活/维持以及 Aurora B 激酶活性调节中的功能。 3) 检查染色体过客复合体是如何调节的染色体上。染色体是否通过生物化学方式激活染色体过客复合物，或者染色体只是用于增加复合物的局部浓度？该提案的研究结果将帮助我们了解正常细胞如何准确地分离染色体，以及这一过程如何在癌细胞和先天缺陷中失败。