The Role of Bub1 in SV40 Large T Mediated Transformation

Bub1 在 SV40 大 T 介导的转化中的作用

基本信息

批准号：
8046358
负责人：
THOMAS M ROBERTS
金额：
$ 40.81万
依托单位：
DANA-FARBER CANCER INST
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8046358
关键词：
Acute Address Agar Alleles Aneuploidy Antigens 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 Pathway interactions Phenotype Phosphorylation Phosphotransferases Play Protein p53 Proteins RNA Interference Retinoblastoma Protein Role Running Serine Simian virus 40 Small Interfering RNA Stress TP53 gene Temperature Time Tumor Suppressor Proteins Viral Viral Tumor Antigens Virus antigen binding base cell transformation gain of function genetic analysis in vivo interest mutant neoplastic premature research study response scaffold senescence sialosyl-T antigen small hairpin RNA tumor

项目摘要

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之间一组有趣的功能相互作用：SV40 Large 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纺锤体组装的检查点蛋白，并被发现在某些以非整倍性为特征的人类癌症。 LT 抗原还可通过以下方式导致基因组不稳定诱发染色体畸变和非整倍体。遗传分析表明 T 的相互作用具有 Bub1 的抗原不是永生化所必需的，但对于 T 抗原驱动病毒复制是必需的并转变。值得注意的是，LT 似乎充当将 Bub1 带到 p53 的支架，然后 p53 被磷酸化 Bub1 直接作用于 ser37，第二种激酶间接作用于 ser15，从而导致 p53 的稳定。初步数据表明 p53 的这种稳定对于 LT 转化至少在某些情况。另外值得注意的是发现通过 LT 表达或在没有 LT 的情况下通过 RNAi 对抗 Bub1，导致 p53 依赖性细胞衰老，并伴有 Ser37 的磷酸化。最近，另一个研究小组证明 ras 会诱导衰老，这我们可以用 Bub1 的显性失活等位基因进行阻断，这也依赖于 p53 丝氨酸的磷酸化 37. 本次资助的关键问题是 Bub1 如何促进 LT 介导的复制和转化并在缺乏 LT 的情况下通过衰老抑制肿瘤形成。我们可以想象几种可能的机制：LT可能使用Bub1通过其直接调节复制和转化 p53 的磷酸化，通过 Bub1 介导 LT 复合体或更多其他靶标的磷酸化间接通过破坏 Bubl 在调节基因组稳定性中的作用。这些机制不必相互排斥的。显然，类似的机制可能在发挥作用，因为 Bub1 可以保护“正常”细胞免受侵害。通过促进衰老来实现转化。在此应用中，我们建议探索其中的每一个机制依次。