Define the role of NUCKS1 in homologous recombination DNA repair and cancer biology

项目摘要/摘要 DNA双链断裂(DSB)是一种剧毒的DNA损伤，可在DNA过程中自发发生 复制，但也是在细胞暴露于化学诱变剂或电离辐射时引入的。DSB可以 导致基因组不稳定和突变，DSB修复缺陷是许多人类疾病的基础，包括 与癌症易感性相关的疾病。 核无处不在的酪蛋白和细胞周期蛋白依赖性蛋白激酶底物1(NUCKS1)是一种高度依赖于细胞周期蛋白的蛋白。 翻译修饰、DNA结合和脊椎动物特有的蛋白质。NUCKS1是RAD51的一个平行对数- 相关蛋白1(RAD51AP1)和同源重组(HR)在DNA修复中的作用。 NUCKS1的下调会损害HR，使人类细胞对化疗药物过敏， 影响复制分叉的稳定性，并增加小鼠对辐射致癌的敏感性。 当细胞暴露于DNA损伤剂时，NUCKS1在几个残基上被磷酸化。然而， 这些修饰对HR反应的表型影响尚不清楚。值得注意的是，损失 NUCKS1下调早期DNA损伤诱导的RAD51灶的形成并导致显著升高 DNA损伤导致的RAD54病灶的持续水平。此外，NUCKS1在功能上与 RAD54。然而，NUCKS1-RAD54复合体的形成如何影响HR和癌症避免尚不清楚。 这一应用将描述NUCKS1的生物学及其与DNA马达蛋白的功能相互作用 RAD54在生化和细胞遗传分析中的应用。我们还将包括对翻译后的分析 修改了NUCKS1和一些精选的癌症相关NUCKS1变体，以更好地了解这些 对HR和DNA复制的影响。综上所述，我们的研究将填补我们在 了解NUCKS1在HR和肿瘤抑制中的作用。 鉴于DSB修复和HR在抑制肿瘤和去除DNA损伤中的重要性 通过电离辐射和其他环境诱变剂，我们的调查结果可能会直接 与改进的环境因素对人类健康的风险预测有关。

PROJECT SUMMARY/ABSTRACT DNA double-strand breaks (DSBs) are highly toxic DNA lesions that can occur spontaneously during DNA replication, but also are introduced upon exposure of cells to chemical mutagens or ionizing radiation. DSBs can lead to genome instability and mutations, and defects in DSB repair underlie many human diseases, including disorders associated with cancer predisposition. Nuclear Ubiquitous Casein and Cyclin-dependent Kinases Substrate 1 (NUCKS1) is a highly post- translationally modified, DNA-binding and vertebrate-specific protein. NUCKS1 is a paralog of RAD51- Associated Protein 1 (RAD51AP1) and functions in DNA repair by homologous recombination (HR). Downregulation of NUCKS1 impairs HR, renders human cells hypersensitive to chemotherapeutic agents, compromises replication fork stability, and increases the susceptibility to radiation carcinogenesis in mice. NUCKS1 is phosphorylated at several residues upon exposure of cells to DNA damaging agents. However, the phenotypic consequences of these modifications on the HR reaction are not understood. Of note, loss of NUCKS1 downregulates the formation of early DNA damage-induced RAD51 foci and leads to greatly elevated and persistent levels of DNA damage-induced RAD54 foci. Moreover, NUCKS1 functionally interacts with RAD54. Yet, how NUCKS1-RAD54 complex formation impacts upon HR and cancer avoidance is not known. This application will delineate the biology of NUCKS1 and its functional interaction with the DNA motor protein RAD54 in biochemical and cell-based genetic assays. We will also include the analysis of post-translationally modified NUCKS1 and of a few select cancer-associated NUCKS1 variants to better understand how these impact upon HR and DNA replication. Taken together, our study will fill critical knowledge gaps in our understanding of NUCKS1 function in HR and tumor suppression. Given the importance of DSB repair and HR in tumor suppression and in the removal of DNA lesions induced by ionizing radiation and other environmental mutagens, the results from our investigation likely will have direct relevance to improved risk predictions for human health from environmental factors.