The Role of Bub1 in SV40 Large T Mediated Transformation

Bub1 在 SV40 大 T 介导的转化中的作用

• 批准号: 7647584
• 负责人: THOMAS M ROBERTS
• 金额: $ 40.17万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7647584
• 关键词: Acute; Address; Agar; Alleles; Aneuploidy; Binding; Binding Sites; Biological; Biological Assay; Cell Aging; Cells; Chromosome abnormality; Chromosomes; Complex; Cytokinesis; DNA Damage; DNA Tumor Viruses; DNA biosynthesis; Data; Dominant-Negative Mutation; EP300 gene; Event; Family member; Fibroblasts; Genome; Genome Stability; Genomic Instability; Grant; Growth; Human; Large T Antigen; Lead; Length; Light; Literature; Long-Term Effects; Malignant Neoplasms; Measures; Mediating; Microscopy; Mitosis; Mitotic; Mitotic spindle; Molecular; Monitor; Mutate; Mutation; Normal Cell; Oncogenes; Papovaviridae; Pathway interactions; Performance; Phenotype; Phosphorylation; Phosphotransferases; Play; Protein p53; Proteins; Retinoblastoma Protein; Role; Running; Simian virus 40; Small Interfering RNA; Stress; TP53 gene; Temperature; Time; Tumor Suppressor Proteins; Viral; Virus; antigen binding; base; gain of function; genetic analysis; in vivo; interest; mutant; neoplastic; premature; research study; response; scaffold; senescence; small hairpin RNA; transforming virus; tumor

We have discovered an interesting set of functional interactions among three proteins: SV40 Large T antigen (LT), the p53 tumor suppressor protein and the mitotic kinase Bub1. Bub1 is a member of the family of checkpoint proteins that monitor the assembly of the mitotic spindle, and has been found to be mutated in certain human cancers characterized by aneuploidy. LT antigen can also cause genomic instability by inducing chromosomal aberrations and aneuploidy. Genetic analysis demonstrates that interaction of T antigen with Bub1 is not required for immortalization but is necessary for T antigen to drive viral replication and transform. Notably LT appears to act as a scaffold bringing Bub1 to p53, which then is phosphorylated on ser37 directly by Bub1 and on ser15, indirectly by a second kinase, leading to the stabilization of p53. Preliminary data suggests that this stabilization fo p53 is necessary for transformation by LT at least in certain circumstances. Also of note is finding that downregulating Bub1 function either by LT expression or by RNAi against Bub1 in the absence of LT, results in p53 dependent cellular senescence, accompanied by phosphorylation of ser37. Recently another group has demonstrated that ras induced senescence, which we can block with a dominant negative allele of Bub1, is also dependent on phosphorylation of p53 at serine 37. The key questions in the context of this grant are how Bub1 contributes to LT mediated replication and transformation and to suppressing tumor formation via senescence in the absence of LT. We can imagine several possible mechanisms: LT may use Bub1 to regulate replication and transformation via its direct phosphorylation of p53, via Bub1 mediated phosphorylation of other targets in the LT complex or more indirectly via by perverting Bubl's role in regulating genome stability. These mechanisms need not be mutually exclusive. Obviously similar mechanisms may be in play as Bub1 guards "normal" cells from transformation by promoting senescence. In this application we propose to probe each of these mechanisms in turn.

我们发现了三种蛋白质中有趣的功能相互作用集：SV40大T 抗原（LT），p53肿瘤抑制蛋白和有丝分裂激酶BUB1。 Bub1是家庭成员 监测有丝分裂主轴组件的检查点蛋白质，并已发现在 某些以非整倍性为特征的人类癌症。 LT抗原也会通过 诱导染色体畸变和非整倍性。遗传分析表明T的相互作用 永生化不需要带有bub1的抗原，但对于t抗原驱动病毒复制是必需的 并转变。 LT值得注意的是将Bub1带到P53的脚手架，然后是磷酸化的 直接通过bub1和ser15上的Ser37上，间接地通过第二个激酶，导致p53的稳定。 初步数据表明，p53的这种稳定对于通过LT至少在 某些情况。值得注意的是，发现BUB1通过LT表达或 在不存在LT的情况下，RNAi反对BUB1，导致p53依赖性细胞衰老，伴随 Ser37的磷酸化。最近，另一组表明RAS诱导衰老，这是 我们可以用BUB1的主要负等位基因阻塞，也取决于丝氨酸p53的磷酸化 37。在这笔赠款背景下的关键问题是Bub1如何对LT介导的复制和 在没有LT的情况下，通过衰老抑制肿瘤形成并抑制肿瘤的形成。我们可以想象 几种可能的机制：LT可以使用BUB1通过其直接调节复制和转换 p53的磷酸化，通过BUB1介导的LT复合物中其他靶标的磷酸化或更多 通过扭曲BUBL在调节基因组稳定性中的作用，间接通过。这些机制不必是 相互排斥。显然，类似的机制可能会发挥作用，因为Bub1守卫从 通过促进衰老来转变。在此应用程序中，我们建议探究其中的每一个 机制依次。