Mechanistic Dissection of the BRCA1-SETX-dependent Pathway of R-loop Avoidance and Genome Maintenance

项目摘要 基因组完整性的维持依赖于细胞修复受损DNA并分解的能力 转录-复制冲突。在这方面，R-环，三链核酸结构， 一种与DNA模板杂交的RNA转录本，可以在多个 方式。具体地说，R环结构中的单链DNA容易发生核溶解切割，从而导致 在转录相关突变或转录相关重组中。此外，碰撞 带有R环的DNA复制机制会导致复制叉坍塌、DNA双链 断裂(DSB)、分叉融合和染色体易位，这些都可能导致肿瘤 转化和肿瘤发生。 这是我们MPI资助的竞争性延续，利用了我们在DNA修复酶学方面的独特专业知识 以及描述R环分解机构的结构-功能的细胞生物学建模，该R环分解机构包括 SF1家族的解旋酶感冒素(SETX)和肿瘤抑制复合体BRCA1-BARD1。在……里面 具体目标1，我们将定义SETX异常多功能的核酸解离活性并进行测试 假设SETX通过特定的解锁活动直接解析R循环。具体目标2 将确定BRCA1-BARD1在SETX介导的R环解析中的作用，以检验以下假设 BRCA1-BARD1与SETX合作，通过询问SETX和 BRCA1-BARD1在我们重组的生化系统和细胞中。 此次MPI续订是基于帕特里克·宋博士长期富有成效的合作。 领先的DNA修复酶学家和加里·库普费尔博士，他是一位利用基因 Fanconi贫血模型，以促进对DNA修复途径和机制的了解。 与众多具有重要意义的合著论文一起，我们持续的合作努力 承诺发挥最大程度的影响，并提供对机械基础的洞察 一条与肿瘤抑制途径相关联的主要基因组维持途径。

Project Summary Maintenance of genomic integrity depends on the ability of cells to repair damaged DNA and resolve transcription-replication conflicts. In this regard, R-loops, three-stranded nucleic acid structures that harbor an RNA transcript hybridized to a DNA template, can compromise genome stability in multiple ways. Specifically, the ssDNA within the R-loop structure is vulnerable to nucleolytic cleavage, resulting in transcription-associated mutagenesis or transcription-associated recombination. Moreover, collisions of the DNA replication machinery with R-loops can cause replication fork collapse, DNA double-strand breaks (DSBs), fork fusions, and chromosome translocations, which can then lead to neoplastic transformation and tumorigenesis. This competitive continuation of our MPI grant leverages our unique expertise in DNA repair enzymology and cell biology modeling to delineate the structure-function of an R-loop resolution machinery comprised of the SF1 family helicase Senataxin (SETX) and the tumor suppressor complex BRCA1-BARD1. In Specific Aim 1, we will define the unusually versatile nucleic acid unwinding activity of SETX and test the hypothesis that SETX resolves R loops directly through specific unwinding activity. Specific Aim 2 will determine the role of BRCA1-BARD1 in SETX-mediated R-loop resolution to test the hypothesis that BRCA1-BARD1 cooperates with SETX to resolve pathological R-loops by interrogating SETX and BRCA1-BARD1 in our reconstituted biochemical systems and in cells. This MPI renewal is based on the longstanding and productive collaboration between Dr Patrick Sung, a leading DNA repair enzymologist, and Dr Gary Kupfer, a physician-scientist who has utilized the genetic model of Fanconi anemia to advance understanding of DNA repair pathways and mechanisms. Together, with numerous coauthored papers of high significance, our continuing collaborative endeavors promise to exert impact of the highest degree and to provide insight into the mechanistic underpinnings of a major genome maintenance pathway that is linked to tumor suppression pathways.