Control of Genomic Stability by Emil and Secruin

Emil 和 Secruin 对基因组稳定性的控制

• 批准号: 6777082
• 负责人: NORMAN LEHMAN
• 金额: $ 16.86万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6777082
• 关键词: antibody; cell cycle proteins; cell growth regulation; cell line; chromosome aberrations; chromosome movement; cyclins; cytogenetics; ligase; mitotic spindle apparatus; molecular oncology; neoplastic process; nervous system neoplasms; protein localization; protein protein interaction; protein structure function; transfection /expression vector; ubiquitin

DESCRIPTION (provided by applicant): Aneuploidy and chromosomal aberrations are common features of human neuroplasms. Genomic instability, or the tendency for mitotic errors to create chromosomal duplications, losses, and translocations has long been recognized as a major mechanism of tumorigenesis. The study of genomic instability promises new insights into cancer treatment. Recently, significant advances have been made in the understanding of the molecular details of the regulation of mitosis. Securin is a protein that functions to ensure accurate distribution of chromosomes to daughter cells by inhibiting anaphase progression until all chromosomes are properly aligned at metaphase. When cells are manipulated to over-or under-express securin they develop chromosomal abnormalities and micronuclei. Such micronuclei are frequently seen in neurological tumors, especially oligogendrogliomas. Another protein, Emi1, recently discovered by the Peter Jackson Laboratory, is involved in S phase activation and mitotic control. Emi1 blocks the degradation of securin by inhibiting its ubiquitination, but also directly binds to securin. Over-expression of Emi1 causes an abnormal prometaphase block and abnormal mitotic spindle formation. We hypothesize that the direct interaction of Emi1 and securin mediates this effect causing genomic instability. Hct116 colon carcinoma cells are a diploid cell line ideal for mitotic studies. I will use these cells as a tool to study the control of genomic stability by Emi1 and securin. I will also address the possible role of Emi1 and securin in the genesis of neurological tumors. The proposed research will specifically address the following questions. Do endogenous Emi1 and securing interact directly in cells, and if so, during which stage(s) of the cell cycle? Is the Emi1-securin interaction localized within the cell? Which functional domains of Emi1 and securin are important in determining their interaction? Does Emi1 misexpression cause spindle abnormalities or chromosomal missegregation, and is securin required for this effect? Does over- or under-expression of Emi1 produce chromosomal aberrations such as deletions or duplications? If so, do specific cytogenetic abnormalities occur? Does Emi1 over-expression induce cellular transformation, or cooperate with known oncogenes such as ras, myc, or securin, in inducing transformation? Does Emi1 misexpression occur in specific tumor types, including neurological tumors? Does Emi1 expression positively or negatively correlate with securin expression in tumors? Does Emi1 or securin expression correlate with activation of the cyclin D/Rb/E2F pathway in tumors? I will pursue an academic career in neuropathology and will apply the knowledge and experience gained from the proposed studies to translational neuro-oncology research.

描述（由申请人提供）：非整倍性和染色体畸变是人类神经质的共同特征。基因组不稳定，或有丝分裂错误造成染色体重复、丢失和易位的倾向，长期以来一直被认为是肿瘤发生的主要机制。基因组不稳定性的研究为癌症治疗带来了新的见解。最近，在了解有丝分裂的分子细节方面取得了重大进展。 Securin 是一种蛋白质，其功能是通过抑制后期进展直至所有染色体在中期正确排列来确保染色体准确分配到子细胞。当细胞被操纵过度或不足表达 securin 时，它们会出现染色体异常和微核。这种微核常见于神经肿瘤，尤其是少突胶质细胞瘤。 Peter Jackson 实验室最近发现的另一种蛋白质 Emi1 参与 S 期激活和有丝分裂控制。 Emi1 通过抑制 securin 泛素化来阻止其降解，但也直接与 securin 结合。 Emi1 的过度表达会导致异常的中期阻滞和异常的有丝分裂纺锤体形成。我们假设 Emi1 和 securin 的直接相互作用介导了这种效应，导致基因组不稳定。 Hct116 结肠癌细胞是二倍体细胞系，非常适合有丝分裂研究。我将使用这些细胞作为工具来研究 Emi1 和 securin 对基因组稳定性的控制。我还将讨论 Emi1 和 securin 在神经肿瘤发生中的可能作用。拟议的研究将具体解决以下问题。内源性 Emi1 和 secure 是否在细胞中直接相互作用？如果是，在细胞周期的哪个阶段？ Emi1-securin 相互作用是否局限于细胞内？ Emi1 和 securin 的哪些功能域对于确定它们的相互作用很重要？ Emi1 错误表达是否会导致纺锤体异常或染色体错误分离？这种效应是否需要 securin？ Emi1 的过度或不足表达是否会产生染色体畸变，例如缺失或重复？如果是这样，是否会发生特定的细胞遗传学异常？ Emi1 过表达是否会诱导细胞转化，或者是否与已知的癌基因（如 ras、myc 或 securin）协同诱导转化？ Emi1 错误表达是否发生在特定肿瘤类型（包括神经肿瘤）中？肿瘤中 Emi1 表达与 securin 表达呈正相关还是负相关？ Emi1 或 securin 表达与肿瘤中细胞周期蛋白 D/Rb/E2F 通路的激活相关吗？我将从事神经病理学的学术生涯，并将从拟议研究中获得的知识和经验应用于转化神经肿瘤学研究。