STRUCTURE AND FUNCTION OF THE SV40 TUMOR ANTIGEN

SV40T抗原与SV40上的序列特异性地相互作用 DNA复制源启动病毒DNA复制并调节 早期和晚期病毒基因的表达。到目前为止，这种交互是 在DNA水平上理解得最好，而对 参与结合的多肽区或结构域 病毒DNA。同样，关于将军的信息也很少 T抗原的二级结构。我们建议检查DNA结合 通过映射与DNA结合的多肽片段来定位T抗原的区域 在体外，第二，通过研究DNA与各种 以前描述的突变T抗原。有关辅助服务器的信息 将通过将内部二硫键映射到 多肽链。总之，这些实验将为我们提供数据 关于这种蛋白质的结构组织，并将使我们能够 更好地了解T抗原的蛋白质成分--SV40 DNA 互动。 T抗原在NH2-和COOH-末端的多个位点被磷酸化 地区。我们之前已经确定这种蛋白质是磷酸化的 在特定的逐步过程中的NH2-末端区域，该过程包括 磷酸化和去磷酸化事件。它的功能是 磷酸化途径尚不清楚，但事实是它高度 受调节表明它与蛋白质的生物化学有关。 牢房。我们计划绘制特定的T抗原残基图谱，这些残基成为 在多肽成熟时发生磷酸化和去磷酸化 手机。此外，我们建议确定是否存在 这些磷酸化状态与DNA或ATP结合活性之间的关系。 最后，因为T抗原的亚群存在于 细胞表面对肿瘤排斥反应的机制很重要，也可能 参与转型，我们建议研究一下这个结构 T抗原部分与寡聚和磷酸化的关系 各州。

The SV40 T antigen specifically interacts with the sequences at the SV40 DNA replication origin to initiate virus DNA replication and to regulate early and late viral gene expression. To date this interaction is understood best at the DNA level and relatively little is known about the polypeptide regions or domains which are involved in the binding to the virus DNA. Likewise, there is little information about the general secondary structure of T antigen. We propose to examine DNA binding regions of T antigen by mapping polypeptide fragments that bind to the DNA in vitro and, secondly, by studying the association of the DNA with various previously characterized mutant T antigens. Information on secondary structure will be obtained by mapping internal disulfide bonds in the polypeptide chain. Together these experiments will provide us with data regarding the structural organization of this protein and will allow us to better understand the protein component of the T antigen - SV40 DNA interaction. T antigen is phosphorylated at multiple sites at the NH2- and COOH-terminal regions. We have previously determined that the protein is phosphorylated at the NH2-terminal region in a specific stepwise process which involves phosphorylation and dephosphorylation events. The function of this phosphorylation pathway is not known but the fact that it is highly regulated suggests that it is linked to the biochemistry of the protein in the cell. We plan to map the specific T antigen residues which become phosphorylated and dephosphorylated as the polypeptide matures in the cell. In addition, we propose to determine if there is a relationship between these phosphorylation states and DNA or ATP binding activity. Finally, because the subpopulation of T antigen which is present at the cell surface is important to the mechanism of tumor rejection and may also be involved in transformation, we propose to study the structure of this fraction of T antigen with respect to oligomerization and phosphorylation states.