Genetic Framework and Molecular Mechanism of Fanconi Anemia

项目摘要 范可尼贫血（FA）是一种由DNA损伤修复缺陷引起的隐性遗传性疾病。FA 患者表现出再生障碍性贫血、先天性畸形和高度升高的癌症， 发生。来自FA患者的细胞对DNA交联剂过敏， 在遗传毒性胁迫下对染色体断裂高度敏感。迄今为止，15个常染色体和 1 X连锁基因被指定为FA的致病基因，但是FA的分子结构是不稳定的。 FA途径在很大程度上仍不清楚。缺乏明确的遗传模型系统， 大多数FA蛋白中可识别的蛋白质结构域是阻碍FA蛋白合成的主要障碍之一。 FA生物学进展。这项建议的主要目的是建立遗传框架 的FA途径，并阐明关键FA蛋白的分子功能。我们开始 通过系统构建体细胞基因敲除模型来解决这些问题。我们 初步研究暗示了一种假设，即不同的FA蛋白形成不同的 功能模块来完成DNA损伤诱导的FA途径激活， 能够募集DNA损伤处理酶。我们计划验证这个假设 有三个具体目标：（1）确定经典FA基因产物之间的上位关系， 这将减轻范可尼贫血基因之间遗传联系的明显空白。（二） 剖析了含有多个FA的FA核心E3连接酶复合物的功能整合 功能未知的蛋白质(3)确定DNA-蛋白质交联是否普遍存在 内源性病变由FA途径处理。FA途径的阐明应具有 在推进对基本细胞机制的理解方面产生了重大影响 保护基因组的完整性更重要的是，FA途径组分是潜在的靶点， 治疗干预FA通路主要在解析复制叉中起作用- 阻断DNA损伤这种类型的病变最常见的例子是DNA交联 通过双功能烷基化化疗方式，如顺铂和美法仑， 以及由电离辐射暴露高频率产生的DNA-蛋白质交联。 例如，许多卵巢癌对顺铂治疗的临床反应取决于它们的治疗效果。 FA通路状态。综上所述，本项目的目的是描绘分子病理 范可尼贫血的机制与发现新的治疗方法的直接利益 目标是改善癌症治疗结果。

Project Summary Fanconi anemia (FA) is a recessive disorder caused by deficient DNA damage repair. FA patients exhibit aplastic anemia, congenital abnormalities, and profoundly elevated cancer occurrence. Cells derived from FA patients are hypersensitivity to DNA crosslinking agents and highly susceptible to chromosome breakage under genotoxic stress. To date, 15 autosomal and 1 X-linked genes are designated as causative genes for FA, but the molecular structure of the FA pathway remains largely unclear. Lack of defined genetic model systems and a scarcity of recognizable protein domains in most FA proteins are among the major obstacles impeding the advance of FA biology. The main objective of this proposal is to establish the genetic framework of the FA pathway and to elucidate molecular functions of key FA proteins. We begin to approach these problems by systematically constructing somatic cellular knockout models. Our preliminary investigations insinuate a hypothesis that different FA proteins form distinct functional modules to accomplish the DNA damage-induced FA pathway activation, which enables the recruitment of DNA damage-processing enzymes. We plan to test this hypothesis with three specific aims: (1) Define the epistatic relationships among classic FA gene products, which will mitigate a visible void in genetic connections among Fanconi anemia genes. (2) Dissect the functional integration of the FA core E3 ligase complex which contains several FA proteins with unknown functions. (3) Determine whether DNA-protein crosslinks are prevalent endogenous lesions processed by the FA pathway. Elucidation of the FA pathway should have a significant impact in advancing the understanding of fundamental cellular mechanisms protecting genome integrity. More importantly, FA pathway components are potential target for therapeutic intervention. The FA pathway functions primarily in resolving replication fork- blocking DNA lesions. This type of lesions is exemplified by DNA crosslinks most frequently generated by bifunctional alkylating chemotherapeutic modalities, such cisplatin and melphalan, and by DNA-protein crosslinks produced with high frequency from ionizing radiation exposure. For example, clinical response of many ovarian cancers to cisplatin treatment is dictated by their FA pathway status. In summary, this project is aimed at delineating the molecular pathological mechanism of Fanconi anemia with the immediate benefit of uncovering novel therapeutic targets to the improve cancer treatment outcomes.