Ku86 Controls DNA Repair, Telomeres & Genomic Stability

描述（由申请人提供）：该资助的具体目的是针对人体细胞中Ku 86：KARP-1基因座的体细胞遗传分析。 在小鼠中，Ku 86、沿着Ku 70、DNA依赖性蛋白激酶催化亚基（DNA-PK[CS]）、XRCC-4、DNA连接酶IV和Artemis是DNA双链断裂（DSB）修复的关键形式（称为非同源末端连接（NHEJ））所必需的。 最近，我们发现Ku 86：KARP-1在人体细胞中起着额外的重要作用。 在这项资助申请中，我们提供了初步的数据来证明这种重要的作用可能与Ku 86：KARP-1调节端粒长度和基因组稳定性的能力有关。 这是第一次证明NHEJ因子之一调节人类细胞中的这两个过程。 我们描述了以下实验，这些实验阐明了Ku 86和KARP-1在人类细胞中DNA DSB修复、端粒长度调节和基因组稳定性中的遗传和分子作用。 鉴定和理解控制人类DNA修复的基因的重要性通过大量癌症易感综合征的存在而得到强调，所述癌症易感综合征例如共济失调毛细血管扩张症、共济失调毛细血管扩张样病症、奈梅亨断裂综合征、范可尼贫血、李-弗劳梅尼综合征、着色性干皮病以及乳腺癌和结肠癌，其中似乎潜在的分子缺陷存在于DNA修复基因中。 我们打算使用四条实验线来表征这些重要的途径：1。 条件性人Ku 86：KARP-1-无效细胞系的构建。 2.为什么人Ku 86：KARP-1-null组织培养的人细胞会发生凋亡？3. DNA-PK活性的丧失是Ku 86：KARP-1无效表型的原因吗？4. Ku 86：KARP-1突变细胞端粒酶生物合成或功能异常这些研究的最终目标是使用Ku 86和KARP-1突变细胞系作为工具来理解人类DNA DSB修复的分子机制。

DESCRIPTION (provided by applicant): The specific aims of this grant are directed towards a somatic cell genetic analysis of the Ku86:KARP-1 locus in human cells. In the mouse, Ku86, along with Ku70, the DNA-dependent protein kinase catalytic subunit (DNA-PK[CS]), XRCC-4, DNA ligase IV and Artemis, are required for a critical form of DNA double strand break (DSB) repair known as nonhomologous end joining (NHEJ). Recently, we have shown that Ku86:KARP-1 plays an additional, essential role in human somatic cells. In this grant application we provide preliminary data to demonstrate that this essential role is probably related to the ability of Ku86:KARP-1 to regulate telomere length and genomic stability. This is the first demonstration that one of the NHEJ factors regulates these two processes in human cells. We describe below experiments that elucidate the genetic and molecular role(s) of Ku86 and KARP-1 in DNA DSB repair, telomere length regulation and genomic stability in human cells. The importance of identifying and understanding the genes that control human DNA repair is underscored by the existence of a large number of cancer predisposition syndromes such as ataxia telangiectasia, ataxia telangiectasia-like disorder, Nijmegen Breakage syndrome, Fanconi's anemia, Li-Fraumeni syndrome, xeroderma pigmentosum and breast and colon cancer where it appears that the underlying molecular defects reside in DNA repair genes. We intend to characterize these important pathways using four lines of experimentation: 1. Construction of conditional human Ku86:KARP-1-null cell lines. 2. Why do human Ku86:KARP-1-null tissue culture human cells undergo apoptosis? 3. Is the loss of DNA-PK activity responsible for the Ku86:KARP-1-null phenotypes? 4. Is telomerase biogenesis or function aberrant in Ku86:KARP-1 mutant cells? The ultimate goal of these studies is to use Ku86 and KARP-1 mutant cell lines as tools to understand the molecular mechanisms of DNA DSB repair in humans.