Pol Epsilon Proofreading and Genetic Stability in Mice

校对是DNA聚合酶保真度的主要守护者。真核生物有两种 校对聚合酶，Pol 5和Pol e，这是忠实的染色体DNA所必需的 复制。为了确定校对的生物学意义，我们用 这些基本聚合酶的外切核酸酶(Exo)结构域失活点突变。 在这里，我们建议将我们新的Pol eexo~突变系与Pol 8 exo“和 错配修复(MMR)突变体，以描绘控制忠实DNA合成和 在哺乳动物中避免癌症。本项目的总体目标是确定生物 Pol e校对的功能。具体目标是：1)描述生存与癌症的关系 Pol eexo“小鼠的表型，2)Pol e exo”细胞的突变子表型和 组织，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电子校对和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电子校对对哺乳动物的意义 生物学、DNA复制保真度和癌症。这些研究奠定了表征的基础 人类的多态，映射到Pol e的校对领域，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.