DNA PK IN RADIATION DAMAGE REPAIR AND LYMPHOMAGENESIS

描述：DNA依赖性蛋白激酶DNA-PK是一种丝氨酸-苏氨酸激酶， 一种由465-kDA催化亚基DNA-PKcs和70 kDA和86-kDa异二聚体DNA靶向组分Ku 70和Ku 80。 基于我们最近对Ku 70- /-和Ku 80-/-小鼠的初步研究以及更早的研究， 其他人对SCID小鼠的研究，假设三种中的每一种都是 DNA-PK的组分可能具有不同但重叠的作用。拟议 研究的目的是测试这一假设，并阐明 DNA-PK各组分在DNA双链中的生理作用 淋巴细胞中链断裂（DSB）修复和V（D）J重组 发育和淋巴瘤发生。有两个具体目标。 具体目标1侧重于个人的生理作用 亚基在DSB修复、V（D）J重组和淋巴细胞发育中的作用。我们 计划产生突变小鼠和细胞系缺乏一个或多个 这些多肽，并使用它们来推断个体的作用， 在T细胞和B细胞发育过程中，以及在 辐射诱导的DSB以及对辐射敏感性的相关影响。 此外，我们还将研究低剂量（非致死性） 电离辐射对这些突变小鼠中V（D）J重组的影响， 评估T细胞和B细胞的发育是否可以通过X- 辐射以及这种恢复是否会促进 淋巴瘤 具体目标II重点关注Ku 70、Ku 80和DNA-PKcs在 淋巴瘤发生和肿瘤发生。我们将测试一个假设， 从我们的初步研究，Ku 70的损失增加了非法的 重组并导致淋巴瘤的发展。使用各种 突变小鼠和细胞系，自发性肿瘤发展和肿瘤 将在体内研究电离辐射的诱导， 体外转化此外，诱导染色体损伤 （染色体畸变和姐妹染色单体交换） X射线照射将被检查，以了解的作用， DNA-PK的单个亚基在维持基因组稳定性中的作用。 拟议的研究应增加关于以下方面的新信息和见解： DNA-PK及其各亚基在细胞内的生理功能 程序性基因重排和基因组稳定性的维持。 此外，我们的研究应该验证Ku 70是否在 淋巴瘤发生，特别是Ku 70是否可以被认为是一种 候选肿瘤抑制基因

DESCRIPTION: DNA-dependent protein kinase DNA-PK is a serine-threonine kinase that consists of a 465-kDA catalytic subunit, DNA-PKcs, and a 70 kDA and an 86-kDa heterodimeric DNA-targeting component, Ku70 and Ku80. Based on our recent pilot studies of Ku70- /- and Ku80-/- mice and earlier studies of SCID mice by others, it is postulated that each of the three components of DNA-PK may have distinct yet overlapping roles. The proposed studies aim at a test of this hypothesis and the elucidation of the physiological roles of the individual components of DNA-PK in DNA double- strand break (DSB) repair and V(D)J recombination, in lymphocyte development and lymphomagenesis. There are two specific aims. Specific Aim 1 focuses on the physiological role(s) of the individual subunits in DSB repair, V(D)J recombination and lymphocyte development. We plan to generate mutant mice and cell lines deficient in one or more of these polypeptides, and use them to deduce the roles of individual components of DNA-PK during T-and B-cell development, and in the repair of radiation-induced DSB and the associated effects on radiation sensitivity. In addition, we will examine the effect of low (non-lethal) does of ionizing radiation on V(D)J recombination in these mutant mice and evaluate whether T- and B-cell development can be restored by X- irradiation and whether such restoration enhances the development of lymphoma. Specific Aim II focuses on the role(s) of Ku70, Ku80 and DNA-PKcs in lymphomagenesis and tumorigenesis. We will test a hypothesis, inferred from our preliminary studies, that the loss of Ku70 enhances illegitimate recombination and leads to the development of lymphoma. Using various mutant mice and cell lines, spontaneous tumor development and tumor induction by ionizing radiation will be studied in vivo, and neoplastic transformation in vitro. In addition, the induction of chromosome damage (chromosome aberrations and sister chromatid exchanges) with and without X-irradiation will be examined with a view to understand the roles of the individual subunits of DNA-PK in the maintenance of genomic stability. The proposed study should add new information and insight regarding the physiological functions of DNA-PK and its individual subunits in programmed gene rearrangement and the maintenance of genomic stability. Furthermore, our studies should verify whether there is a role of Ku70 in lymphomagenesis, and specifically whether Ku70 may be considered as a candidate tumor suppressor gene.