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类细胞中Ku86:KARP-1位点的体细胞遗传分析。在小鼠中，Ku86和Ku70、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，即非同源末端连接（NHEJ）所必需的。最近，我们发现Ku86:KARP-1在人类体细胞中起着额外的重要作用。在这项拨款申请中，我们提供了初步数据来证明这种重要作用可能与Ku86:KARP-1调节端粒长度和基因组稳定性的能力有关。这是首次证明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，阐明了Ku86和KARP-1在人类细胞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。识别和理解控制人类DNA修复的基因的重要性被大量癌症易感综合征的存在所强调，如共济失调毛细血管扩张症、共济失调毛细血管扩张样疾病、奈梅根断裂综合征、范可尼贫血、Li-Fraumeni综合征、色素性干皮病、乳腺癌和结肠癌，其中潜在的分子缺陷似乎存在于DNA修复基因中。我们打算用四个实验线来描述这些重要的途径：1。条件人Ku86: karp -1缺失细胞系的构建。2. 为什么Ku86: karp -1缺失的人组织培养细胞会发生凋亡？3. DNA-PK活性的丧失是Ku86: karp -1缺失表型的原因吗？4. 端粒酶在Ku86:KARP-1突变细胞中的生物发生或功能异常？这些研究的最终目的是利用Ku86和KARP-1突变细胞系作为工具，了解人类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.