STRUCTURE/FUNCTION OF THE SV40 TUMOR ANTIGEN

猿猴病毒40（SV4O）肿瘤（T）抗原在免疫调节中起着至关重要的作用。 启动和维持SV40 DNA在病毒感染的 猴子细胞这种蛋白质，沿着DNA和细胞因子 参与，作为一个模型，以了解真核DNA复制。的 许多不同实验室的工作提供了唯一的见解， 参与了这一进程，但缺乏这一事件的许多细节。在 特别是，对T抗原 结合并在结构上扭曲了起源。同样地，我们对 这种蛋白质是如何在起始点和复制点解开DNA的 分叉，或者是关于分子间相互作用的性质和功能 T抗原和参与DNA复制的细胞因子之间的关系。我们 一种方法是使许多单点取代突变， 蛋白质中的起始结合结构域和其他地方，并确定 这些突变对各种生化反应的影响， 在DNA合成的起始和繁殖过程中的位置。这样我们 已经鉴定出氨基酸可能直接或间接地 参与起源结合、非特异性DNA结合、结构结合 起源的扭曲，起源解旋，寡聚化，和 DNA在体内的复制通过研究WT和各种突变蛋白， 建议详细研究T抗原制备的机制， 复制的起点通过融化和解旋， 在起点和复制叉处解开DNA， T抗原与细胞蛋白质促进DNA复制， T抗原在DNA复制后期。这样，我们希望 更好地理解病毒和细胞DNA复制的过程 会发生

The simian virus 40 (SV4O) tumor (T) antigen plays a crucial role in initiating and maintaining the replication of SV40 DNA in virus-infected monkey cells. This protein, along with the DNA and cellular factors involved, serves as a model to understand eukaryotic DNA replication. The work of many different labs has provided sole insights into the steps involved in this process but many details of this event are lacking. In particular, little is understood about the mechanism by which T antigen binds to and structurally distorts the origin. Likewise, we know little about how this protein unwinds the DNA at the origin and at replication forks, or about the nature and function of the molecular interactions between T antigen and the cellular factors engaged in DNA replication. Our approach has been to make numerous single-point substitution mutations in the origin-binding domain and elsewhere in the protein and to determine the effects of these mutations on various biochemical reactions that take place during initiation and propagation of DNA synthesis. In this way, we have identified amino acids that are likely to directly or indirectly participate in origin binding, nonspecific DNA binding, structural distortion of the origin, origin unwinding, oligomerization, and replication of DNA in vivo. By studying WT and various mutant proteins we propose to examine, in detail, the mechanisms by which T antigen prepares the origin for replication by melting and untwisting it, the way it unwinds DNA at the origin and at replication forks, how the interaction of T antigen with cellular proteins promotes DNA replication, and the role of T antigen in later stages of DNA replication. In this way, we hope to better understand the process by which viral and cell DNA replication takes place.