Mechanisms and Regulation of Human Translesion DNA Polymerases

项目总结 复制DNA聚合酶(Pols)复制染色体DNA，但在DNA损伤引起的损伤时停滞不前 探员们。因此，专门的跨损伤POL进化成促进复制而不是DNA损伤，从而 允许细胞在基因毒剂的作用下增殖。然而，经病变波极容易出错，而且 从而导致突变，从而导致肿瘤的发生。 POL是新近发现的一种跨损伤POL，参与双链断裂(DSB)修复。 在乳腺和结直肠中，高水平的Pol1基因的过度表达导致基因组不稳定 癌症，这与较差的临床结果相对应。然而，降低POL的表达水平， 使各种肿瘤细胞对辐射敏感。因此，POL的抑制剂可能会增加疗效和 放射治疗的特异性。具体目标1将确定和表征用于以下目的的POL抑制剂 潜在的癌症疗法。 由于跨病变POL容易出错，有必要对这些酶进行严格的调节，以最大限度地减少 突变和癌症风险。跨损伤POL是如何被调节和招募到DNA损伤部位的是 人们对此知之甚少。特定目标2将调查跨病变POL的调节和募集 在跨病变合成过程中。 除了绕过损伤，POL还复制被称为D-环的DNA重组中间产物 在维修DSB过程中形成。人们对刑警组织如何履行这一重要职能知之甚少。特定的 目的3研究POL延伸D-环重组中间体的机制。 在指导阶段(目标1)进行的研究将使用高通量筛查和X光 结晶学以鉴定和表征在癌症治疗中潜在应用的波尔的抑制剂。 在独立阶段(目标2和3)进行的研究最初将侧重于机制和 作为模型酶的人多酚的调节。这些研究随后将扩展到被牵连的POL 在与POL相同的途径中，如翻译合成和D-环延伸。拟议的研究是 可能为DNA损伤耐受和癌症的分子机制提供重要的见解 生物学。

Project summary Replicative DNA polymerases (pols) copy chromosomal DNA, but stall at lesions caused by DNA damaging agents. Specialized translesion pols have therefore evolved to promote replication past DNA damage thus allowing cells to proliferate in the face of genotoxic agents. Translesion pols are, however, error-prone and thus induce mutations which can lead to tumorigenesis. Pol is a newly discovered translesion pol which is involved in double-strand break (DSB) repair. Overexpression of pol causes genome instability and high levels of the pol are found in breast and colorectal cancers, which corresponds to a poor clinical outcome. Reducing the expression level of pol , however, sensitizes various tumor cells to radiation. Inhibitors of pol are therefore likely to increase the efficacy and specificity of radiation therapy. Specific Aim 1 will identify and characterize inhibitors of pol for potential cancer therapeutics. Since translesion pols are error-prone, stringent regulation of these enzymes is necessary for minimizing mutagenesis and cancer risk. How translesion pols are regulated and recruited to sites of DNA damage is poorly understood. Specific Aim 2 will investigate the regulation and recruitment of translesion pol during translesion synthesis. In addition to bypassing lesions, pol replicates DNA recombination intermediates called D-loops which are formed during the repair of DSBs. How pol performs this important function is poorly understood. Specific Aim 3 will investigate the mechanism by which pol extends D-loop recombination intermediates. Studies perfomed during the mentored stage (Aim 1) will use high-throughput screening and X-ray crystallography to identify and characterize inhibitors of pol for potential applications in cancer therapeutics. Research performed during the independent stage (Aims 2 and 3) will initially focus on the mechanisms and regulation of human pol as a model enzyme. These studies will then be extended to pol which is implicated in the same pathways as pol such as transleson synthesis and D-loop extension. The proposed research is likely to provide significant insight into the molecular mechanisms of DNA damage tolerance and cancer biology.