Pol Epsilon Proofreading and Genetic Stability in Mice

校对是DNA聚合酶保真度的主要监护人。真核生物有两个 校正聚合酶，Pol 5和Pol e，它们是忠实的染色体DNA所必需的 复制的为了确定校对的生物学意义，我们制造了“敲入”小鼠， 使这些必需聚合酶的核酸外切酶（exo）结构域中的点突变失活。 在这里，我们提出表征我们的新Pol eexo-突变系，连同Pol 8 exo”和Pol 8 exo“。 错配修复（MMR）突变体，以描绘控制忠实DNA合成的途径， 哺乳动物的癌症预防这个项目的总体目标是确定生物学 Pol e校对的功能。具体目标是：1）表征生存和癌症 2）表征Pol eexo”细胞的突变体表型， 3）确定哺乳动物Pol 6和Pol e校对的功能关系，以及 4)确定Pol e校正和MMR在突变和癌症中的协同作用 回避总之，这些研究将揭示Pol e校对对哺乳动物的意义。 生物学、DNA复制保真度和癌症。这些研究为表征 人类多态性，映射到Pol e的校对域，并提供工具， 开发利用复制错误灾难进行抗肿瘤治疗的新策略。

Proofreading is the primary guardian of DNA polymerase fidelity. Eukaryotes have two proofreading polymerases, Pol 5 and Pol e,that are required for faithful chromosomal DNA replication. To determine the biologic significance of proofreading, we made "knock-in" mice with inactivating point mutations in the exonuclease (exo) domains of these essential polymerases. Here we propose to characterize our new Pol eexo~ mutant line, together with Pol 8 exo" and mismatch repair (MMR) mutants, to delineate pathways that govern faithful DNA synthesis and cancer avoidance in mammals. The overall obective of this project is to determine the biologic functions of Pol e proofreading. The specific aims are: 1) characterize the survival and cancer phenotypes of Pol eexo" mice, 2) characterize the mutator phenotype of Pol e exo" cells and tissues, 3) determine the functional relationship of mammalian Pol 6 and Pol e proofreading, and 4) determine the cooperative roles of Pol eproofreading and MMR in mutation and cancer avoidance. Together, these studies will reveal the significance of Pol eproofreading to mammalian biology, DNA replication fidelity and cancer. These studies lay the groundwork for characterizing human polymorphisms that map to the proofreading domain of Pol e, and provide tools for developing novel strategies that exploit replication error-catastrophe for anti-tumor therapy.