PARVOVIRUS DNA REPLICATION--NS1 AND DNA POLYMERASE DELTA

自主复制的细小病毒含有线性单链 DNA基因组约5千碱基。它们分布广泛， 无脊椎动物，鸟类和哺乳动物，包括人类。细小病毒 非结构蛋白NSI在调节细小病毒中具有核心作用 复制的NS1有6种表型：1.正调控 外壳蛋白启动子，2.自身基因的负调控， 异源基因表达，3.细小病毒DNA要求 复制，4.如果病毒末端来自质粒， 5.抑制SV40 DNA复制，和6.细胞DNA抑制 复制的我们的证据表明，所有或几乎所有的细小病毒DNA 复制需要DNA聚合酶δ。我们建议使用特定地点 突变，研究NSI在病毒DNA复制中的作用， 与PolDelta交互。细小病毒DNA复制受到限制， 正常的人成纤维细胞和这种限制是缓解肿瘤 转型正常细胞中的缺陷是在病毒DNA水平上 复制，不能归因于病毒基因缺陷 表达，而不是它似乎是由于缺乏核 NSI易位。这个项目将研究DNA的功能 聚合酶δ和NSI在病毒和细胞DNA复制中的作用 正常和肿瘤之间病毒DNA复制缺陷 转化细胞

The autonomously replicating parvoviruses contain linear single-stranded DNA genomes of about 5 kilo bases. They are widespread and infect invertebrates, birds, and mammals including man. The parvovirus nonstructural protein NSI has a central role in regulating parvovirus replication. NS1 has been assigned 6 phenotypes: 1. positive regulation of the coat protein promoter, 2. negative regulation of its own gene and heterologous gene expression, 3. requirement for parvovirus DNA replication, 4. requirement for excision if viral termini from a plasmid, 5. inhibition of SV40 DNA replication, and 6. inhibition of cell DNA replication. Our evidence suggests that all or nearly all parvovirus DNA replication requires DNA polymerase delta. We propose to use site-specific mutagenesis to study the roles of NSI in viral DNA replication and its interaction with pol delta. Parvovirus DNA replication is restricted in normal human fibroblasts and this restriction is relieved by neoplastic transformation. The defect in normal cells is at the level of viral DNA replication and it cannot be ascribed to a deficiency in viral] gene expression, rather it appears to result from a deficiency in nuclear translocation of NSI. This project will study the functions of DNA polymerase delta and NSI in viral and cellular DNA replication and explore the defect in viral DNA replication between normal and neoplastically transformed cells.