Regulation of stalled fork repair in mammalian cells

项目摘要 在复制叉停滞位点启动的无错误DNA修复对于预防基因组损伤至关重要。 循环电池的不稳定性。停滞的分叉修复缺陷直接与癌症和其他人类疾病有关。 疾病范可尼贫血（FA）是一种罕见的常染色体隐性（或X连锁）疾病，由失活的 几种FA基因之一。FA的临床表现包括儿童贫血和进行性贫血。 骨髓衰竭、身材矮小和影响多种器官的先天性缺陷。的 癌症（包括实体瘤）的风险升高，尤其是急性髓性白血病的发病率更高。 白血病发现编码核酸酶协调支架蛋白SLX 4/FANCP的基因突变， 一些患有范可尼贫血的个体，并通过与 核酸酶MUS 81、XPF和SLX 1。我们采用了大肠杆菌Tus/Ter复制叉停滞 复合物用于哺乳动物细胞，并已使用它来引发位点特异性复制叉停滞， 在哺乳动物染色体的限定基因座处的同源重组（HR）。我们发现，SLX 4发挥了 在介导Tus/Ter诱导的无错误HR中起关键作用。此功能仅限于失速叉修复， 不是由常规染色体双链断裂诱导的HR的特征。在这里提出的工作中，我们 将使用Scully实验室开发的新工具来分析SLX 4如何调节同源重组， 已停止的复制分叉。我们将使用物理和基因组分析来测量特定的DNA结构， 在Tus/Ter分叉处形成，并将决定SLX 4是否调节Tus/Ter分叉的形成或代谢。 这些DNA结构。该项目将确定SLX 4协调停滞的分叉的机制 处理以在面对复制压力时保持基因组稳定性。这项工作的成功将导致 用于癌症和其他人类疾病治疗的新靶点的鉴定。

PROJECT SUMMARY Error-free DNA repair initiated at the sites of replication fork stalling is critical to the prevention of genomic instability in cycling cells. Defects in stalled fork repair have been directly implicated in cancer and other human diseases. Fanconi Anemia (FA) is a rare, autosomal recessive (or X-linked) disease caused by inactivation of any one of several FA genes. The clinical manifestations of FA include childhood anemia and progressive bone marrow failure, together with short stature and congenital defects affecting a wide variety of organs. The risk of cancer, including solid tumors, is elevated, with particularly high incidence of acute myelogenous leukemia. The gene encoding a nuclease-coordinating scaffolding protein, SLX4/FANCP, is found mutated in some individuals with Fanconi anemia and has been implicated in stalled fork repair through interactions with the nucleases MUS81, XPF and SLX1. We adapted the Escherichia coli Tus/Ter replication fork arrest complex for use in mammalian cells and have used it to provoke site-specific replication fork stalling and homologous recombination (HR) at defined loci of a mammalian chromosome. We find that SLX4 plays a crucial role in mediating error-free HR induced by Tus/Ter. This function is restricted to stalled fork repair and is not a feature of HR induced by a conventional chromosomal double strand break. In work proposed here, we will use novel tools developed by the Scully lab, to analyze how SLX4 regulates homologous recombination at stalled replication forks. We will use physical and genomic assays to measure specific DNA structures that form at the Tus/Ter-stalled fork and will determine whether SLX4 regulates the formation or metabolism of these DNA structures. This project will identify the mechanisms by which SLX4 coordinates stalled fork processing to preserve genome stability in the face of replication stress. Success in this work will lead to the identification of new targets for therapy in cancer and other human diseases.