FANCM in repair of stalled replication forks

DNA结构异常部位的复制分叉停滞是基因组不稳定的公认原因。 复制分叉停滞增加(“复制压力”)是癌细胞的一个共同特征，这表明 对停滞的叉子的有缺陷的处理是癌症基因组不稳定的常见机制。范可尼 贫血(FA)途径在复制叉停滞的新陈代谢和修复过程中起着重要作用。FA是一种罕见的， 由几个FA基因中的任何一个失活引起的常染色体隐性遗传(或X连锁)疾病。临床部 FA的表现包括儿童贫血和进行性骨髓衰竭，以及 影响各种器官的身高和先天缺陷。癌症的风险，包括实体瘤，是 升高，急性髓系白血病的发病率特别高。编码早期病毒的基因 FA途径的应答因子FANCM在一些乳腺癌中被发现突变。FA途径重叠 在功能上与遗传性乳腺癌/卵巢癌易感性的BRCA途径有关--这是 同源重组。FA途径也被复制应激激活，这表明Fa途径在 人类癌症和许多其他疾病中的FA基因。因此，破译人的行为机制 FA途径对人类健康具有广泛的意义。我们最近对大肠杆菌Tus/Ter进行了改造 用于哺乳动物细胞的复制分叉抑制复合体，并用它来量化无错误和 哺乳动物染色体复制叉块引起的易出错的同源重组。更多 最近，我们在哺乳动物细胞中发现了一种新的复制叉阻滞异常修复产物，其中 小的(&lt；10kb)微同源介导的串联复制在复制停止处形成。FANCM 在抑制这些失速的叉子上的异常修复产品方面起着至关重要的作用。在这里提出的工作中，我们 将使用Scully实验室最近开发的新工具来分析FANCM如何调节同源 在停滞不前的复制分叉处进行重组。我们将确定FANCM压制的机制 停滞不前的叉子上的串联复制。这项工作的成功将导致确定新的治疗靶点。 癌症和其他人类疾病。

Replication fork stalling at sites of abnormal DNA structure is a recognized cause of genomic instability. Increased replication fork stalling (“replication stress”) is a common feature of cancer cells, suggesting that defective processing of the stalled fork is a common mechanism of genomic instability in cancer. The Fanconi Anemia (FA) pathway has a major role in the metabolism and repair of stalled replication forks. 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 an early responder of FA pathway, FANCM, is found mutated in some breast cancers. The FA pathway overlaps functionally with the BRCA pathway of hereditary breast/ovarian cancer predisposition—a critical regulator of homologous recombination. The FA pathway is also activated by replication stress, indicating a general role for the FA genes in human cancer and in many other diseases. Thus, deciphering the mechanisms of action of the FA pathway has broad significance for human health. We recently adapted the Escherichia coli Tus/Ter replication fork arrest complex for use in mammalian cells and have used it to quantify both error-free and error-prone homologous recombination induced by a mammalian chromosomal replication fork block. More recently, we identified a novel aberrant repair product of replication fork arrest in mammalian cells, in which small (<10 kb) microhomology-mediated tandem duplications form at the site of replication arrest. FANCM plays a crucial role in suppressing these aberrant repair products at stalled forks. In work proposed here, we will use novel tools, recently developed by the Scully lab, to analyze how FANCM regulates homologous recombination at stalled replication forks. We will identify the mechanisms by which FANCM suppresses tandem duplication at stalled forks. Success in this work will lead to the identification of new targets for therapy in cancer and other human diseases.