STRUCTURE AND FUNCTION OF THE SV40 TUMOR ANTIGEN

SV 40 T抗原特异性地与SV 40 启动病毒DNA复制并调节 早期和晚期病毒基因表达。 到目前为止，这种相互作用是 在DNA水平上了解得最好，而对DNA的了解相对较少。 多肽区域或结构域，所述多肽区域或结构域参与与所述多肽的结合。 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 通过定位结合DNA的多肽片段， 第二，通过研究DNA与各种 先前表征的突变T抗原。 中学信息 结构将通过映射内部二硫键获得， 多肽链 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-SV 40 DNA的蛋白质组分 互动 T抗原在NH 2-和COOH-末端的多个位点磷酸化 地区 我们先前已经确定蛋白质是磷酸化的 在NH 2-末端区域，在特定的逐步过程中， 磷酸化和去磷酸化事件。 这个的作用 磷酸化途径是未知的，但事实上，它是高度 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， 随着多肽在细胞中成熟， cell. 此外，我们建议确定是否存在关系 这些磷酸化状态和DNA或ATP结合活性之间的关系。 最后，由于存在于T细胞上的T抗原亚群， 细胞表面对肿瘤排斥机制很重要， 参与转型，我们建议研究这种结构， T抗原的寡聚化和磷酸化部分 states.

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.