Structure-Function Studies Of DNA Replication Fidelity

今年，有时只与该小组合作，有时与NIH和其他地方的其他小组的科学家合作，我们取得了一些成就。(1)我们确定了酵母DNA聚合酶zeta，这在确定自发和DNA损伤诱导的真核生物诱变率的增变剂衍生物的遗传特性。 (2)我们发表了几项研究，揭示了DNA聚合酶delta和delta在复制核基因组上的前导链和滞后链中的作用。 (3)我们证明了线粒体dNTPs中微量的8-oxo-dGTP降低了DNA聚合酶γ复制保真度，从而可能导致与线粒体疾病相关的线粒体基因组不稳定性。 (4)我们提供的证据表明，DNA聚合酶λ催化循环过程中DNA链的错位发生在dNTP诱导的模板链的重新定位。 (5)我们证明了DNA聚合酶λ可以在连接断裂的DNA末端，即使这些末端含有病变的功能。 (6)我们证明了人DNA聚合酶θ的低保真度DNA合成，与其在跨损伤DNA合成和免疫球蛋白基因的体细胞超突变中的可能作用一致。（8）我们使用从头算QM/MM研究研究了人DNA聚合酶λ与Mg 2+和Mn 2+正确掺入核苷酸的催化机制。 (9)我们发表了关于（a）哺乳动物X家族四种DNA聚合酶之间的结构-功能关系，（B）TLS聚合酶和（c）主要真核复制DNA聚合酶的作用的全面综述。

This year, sometimes with the group only and other times in collaboration with scientists in other groups within NIH and elsewhere, we had several accomplishments. (1) We identified and genetically characterized a mutator derivative of yeast DNA polymerase zeta, which has a critical role in determining the rate of both spontaneous and DNA damage-induced mutagenesis in eukaryotes. (2) We published several studies that reveal the roles of DNA polymerases delta and epsilon in replicating the leading and lagging strands on the nuclear genome. (3) We demonstrated that trace amounts of 8-oxo-dGTP in mitochondrial dNTPs reduce DNA polymerase gamma replication fidelity, thereby possibly contributing to mitochondrial genome instability associated with mitochondrial diseases. (4) We provided evidence that DNA strand misalignment during catalytic cycling by DNA polymerase lambda occur during dNTP-induced repositioning of the template strand. (5) We demonstrated that DNA polymerase lambda can function in joining broken DNA ends even when these ends contain lesions. (6) We demonstrated low fidelity DNA synthesis by human DNA polymerase theta, consistent with its possible roles in translesion DNA synthesis and somatic hypermutation of immunoglobulin genes, (8) We investigated the catalytic mechanism for correct nucleotide incorporation by human DNA polymerase lambda with Mg2+ and Mn2+ using ab initio QM/MM studies. (9) We published comprehensive reviews on (a) structure-function relationships among the four mammalian X family DNA polymerases, (b) TLS polymerases and (c) the roles of the major eukaryotic replicative DNA polymerases.