Role of Bub1 in SV40 large T antigen mediated transformation and replication

Bub1 在 SV40 大 T 抗原介导的转化和复制中的作用

• 批准号: 7683275
• 负责人: Ole Gjoerup
• 金额: $ 37.33万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-10 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7683275
• 关键词: Accounting; Acute; Affect; Aneuploidy; Binding; Binding Proteins; Biological Models; Cell Cycle; Cell division; Cells; Chromosomal Instability; Chromosome abnormality; Chromosomes; Complex; Cytokinesis; DNA; DNA Damage; DNA Tumor Viruses; DNA biosynthesis; Elements; Exhibits; Genome; Human; Impairment; In Vitro; Kinetochores; Large T Antigen; Lead; Life Cycle Stages; Light; Link; Literature; Malignant - descriptor; Malignant Conversion; Malignant Neoplasms; Maps; Mediating; Microscopy; Mitosis; Mitotic; Modeling; Molecular; Monitor; Mutate; Mutation; Nature; Nuclear; Oncogenic; Pathway interactions; Phenotype; Phosphorylation; Phosphotransferases; Ploidies; Process; Protein p53; RNA Interference; Regulation; Role; Signal Transduction; Simian virus 40; Sister Chromatid; Site; TP53 gene; Tetraploidy; Time; Viral; Viral Tumor Antigens; Virus; antigen binding; attenuation; base; cell growth; cellular targeting; gain of function; genetic analysis; in vivo; insight; novel; premature; public health relevance; response; scaffold; senescence; sialosyl-T antigen; tumor; tumorigenesis; viral DNA

DESCRIPTION (provided by applicant): SV40 large T antigen (LT) is a powerful model to study DNA replication and malignant transformation. We have identified an interaction of LT with the mitotic regulator Bub1. Bub1 is critical for preserving genome integrity. It primarily acts at the spindle checkpoint, where it serves a critical function in monitoring tension and attachment at sister chromatid kinetochores. Bub1 is mutated in certain human cancers characterized by aneuploidy. LT binding to Bub1 leads to attenuation of the spindle checkpoint. We hypothesize that binding of Bub1 to LT accounts for some of LT's ability to destabilize the host genome, in particular the ability to induce tetraploidy. Genetic analysis shows that LT binding to Bub1 is required not only for oncogenic transformation but also for viral DNA replication. Our analysis further demonstrates that LT binding to Bub1 is linked to p53 stabilization, which is likely a consequence of a DNA damage response. Our observations are consistent with a model whereby LT acts as a molecular scaffold to direct Bub1 to phosphorylate targets such as p53. The interaction with Bub1 suggests novel roles for LT that may shed light on how it causes chromosome aberrations, stabilization of p53 and transformation. We propose the following aims to study the interaction in detail: 1. Determine mechanistically how LT transforms via Bub1 and the potential contribution of a p53 gain of function 2. Characterize how LT uses Bub1 to induce tetraploidy and DNA damage responses 3. Elucidate how LT promotes viral replication via Bub1 binding. PUBLIC HEALTH RELEVANCE: Studies of the large T antigen of the SV40 DNA tumor virus have provided significant insight on basic mechanisms required for tumor induction and accurate duplication of DNA molecules (replication). Critical cellular targets such as the p53 tumor suppressor were first identified using this model. We have characterized a novel binding partner for T antigen called Bub1. Interestingly, Bub1 closely monitors and safeguards cell division, a process that T antigen has long been suspected to disrupt and thereby cause chromosomal abnormalities. Bub1 mutations are found in certain human cancers also characterized by chromosomal abnormalities. Our proposal will investigate how mechanistically T antigen binding to Bub1 is required for malignant conversion and replication. In the process, we expect to gain a better understanding of normal Bub1 function, and how its compromise facilitates tumorigenesis.

描述（申请人提供）：SV40大T抗原（LT）是研究DNA复制和恶性转化的强大模型。我们已经确定了LT与有丝分裂调节因子Bub1的相互作用。Bub1对保持基因组完整性至关重要。它主要在纺锤体检查点起作用，在那里它在监测姐妹染色单体着丝点的张力和附着方面起关键作用。Bub1在某些以非整倍体为特征的人类癌症中发生突变。LT与Bub1结合导致纺锤体检查点的衰减。我们假设，Bub1与LT的结合在一定程度上解释了LT破坏宿主基因组稳定性的能力，特别是诱导四倍体的能力。遗传分析表明，LT与Bub1的结合不仅是致癌转化所必需的，也是病毒DNA复制所必需的。我们的分析进一步表明，LT与Bub1的结合与p53的稳定有关，这可能是DNA损伤反应的结果。我们的观察结果与LT作为分子支架指导Bub1磷酸化p53等靶标的模型一致。与Bub1的相互作用提示了LT的新作用，可能揭示了它如何导致染色体畸变、p53的稳定和转化。我们提出以下目标来详细研究这种相互作用：1。确定LT如何通过Bub1转化的机制以及p53功能获得的潜在贡献2。描述LT如何使用Bub1诱导四倍体和DNA损伤反应3。阐明LT如何通过Bub1结合促进病毒复制。公共卫生相关性：对SV40 DNA肿瘤病毒的大T抗原的研究为肿瘤诱导和DNA分子精确复制（复制）所需的基本机制提供了重要的见解。关键的细胞靶点，如p53肿瘤抑制因子，首次使用该模型确定。我们已经描述了一种新的T抗原结合伙伴，称为Bub1。有趣的是，Bub1密切监视和保护细胞分裂，这一过程长期以来一直被怀疑是T抗原破坏的，从而导致染色体异常。在某些以染色体异常为特征的人类癌症中发现了Bub1突变。我们的建议将研究T抗原与Bub1结合的机制是如何需要恶性转化和复制的。在这个过程中，我们期望更好地了解正常的Bub1功能，以及它的妥协如何促进肿瘤的发生。