Investigation of a Novel Role for RNA Binding Proteins in DNA Repair

描述(由申请人提供)：这是一项研究有助于DNA双链断裂(DSB)修复的效率和准确性的蛋白质的提案。电离辐射沿着离散的轨道沉积能量，导致成簇的DNA损伤和双链断裂。修复这些标志性病变的能力是正常组织和肿瘤对辐射敏感性和抵抗力的主要决定因素。因此，操纵DNA修复通路为提高放射治疗的疗效提供了一条很有前途的途径。最近的工作为人类RNA结合蛋白小家族参与DSB修复提供了新的证据。这些蛋白质是副蛋白的核心成分，副蛋白是围绕着一个长的非编码RNA支架组织的核结构，通过保留腺苷到肌苷超编辑的mRNAs来调节基因的表达。然而，单独的实验表明，这些蛋白质参与了同源重组和非同源末端连接，这是人类细胞中DSB修复的两条主要途径。人类该家族的三个成员-PSF、p54nrb和PSPC1-迅速重新定位到诱导DNA损伤的位置，这表明存在控制RNA与DNA相互作用的分子开关。需要检验的假设是，PSF及其合作伙伴是基因调控和DNA修复的中介，在DNA损伤诱导后，这些中介会在RNA和DNA相互作用模式之间迅速切换。一个统一的主题可能是依赖PSF及其合作伙伴的内在能力来促进远距离核酸片段的配对。第一个具体目标将是测试PSF7p54nrb复合体促进环状结构中相反DNA末端并置的预测。第二项是利用人类细胞的遗传操作，更广泛地检查PSF及其伙伴的修复功能。第三个将直接关注PSF及其合作伙伴如何在RNA生物发生和DSB修复模式之间切换，并将调查这一机制的治疗适用性。这项研究具有创新性，因为PSF、p54nrb和PSPC1的一级序列和结构域结构不同于任何以前描述的DSB修复蛋白。这项工作具有科学意义，因为它探索了DSB修复和非编码RNA的生物学之间以前未被怀疑的联系，这是细胞生物学中一个有趣和热门的领域。最后，这项工作具有潜在的临床和翻译影响，因为治疗性RNA可能被开发成影响RNA生物发生和DNA修复模式之间的切换，以改变临床放射反应。

DESCRIPTION (provided by applicant): This is a proposal to investigate proteins that contribute to the efficiency and accuracy of DNA double-strand break (DSB) repair. Ionizing radiation deposits energy along discrete tracks, resulting in clustered DNA damage and DSBs. The ability to repair these signature lesions is a major determinant of radiation sensitivity and resistance in both normal tissue and tumors. Manipulation of DNA repair pathways therefore affords a promising approach for improving the efficacy of radiotherapy. Recent work provides evidence for the novel involvement of a small family of human RNA binding proteins in DSB repair. These proteins are core components of paraspeckles, which are nuclear structures that are organized around a long noncoding RNA scaffold and that regulate gene expression by retaining adenosine-to- inosine hyper-edited mRNAs. Separate experiments indicate, however, that these proteins participate in both homologous recombination and nonhomologous end joining, which are the two main pathways of DSB repair in human cells. The three members of the family in humans-PSF, p54nrb, and PSPC1-rapidly relocalize to sites of induced DNA damage, suggesting the existence of a molecular switch that controls RNA versus DNA interaction. The hypothesis to be tested is that PSF and its partners are mediators of gene regulation and DNA repair that switch rapidly between RNA and DNA interaction modes following the induction of DNA damage. A unifying theme may be reliance on an intrinsic ability of PSF and its partners to promote pairing of distant nucleic acid segments. The first specific aim will be to test a prediction that a PSF7p54nrb complex promotes juxtaposition of opposing DNA ends in a loop structure. The second will be to examine repair functions of PSF and its partners more broadly using genetic manipulation of human cells. The third will focus directly on how PSF and its partners switch between RNA biogenesis and DSB repair modes and will investigate the therapeutic applicability of this mechanism. The proposed research is innovative, because the primary sequence and domain structure of PSF, p54nrb, and PSPC1 are unlike any previously characterized DSB repair proteins. The work is scientifically significant, because it explores a previously unsuspected link between DSB repair and the biology of non-coding RNAs, which is an interesting and topical area in cell biology. Finally, the work has potential clinical and translational impact, because of the possibility that therapeutic RNAs might be developed to influence switching between RNA biogenesis and DNA repair modes to alter clinical radiation response.