CLONING & CHARACTERIZING THE XP VARIANT MUTATOR GENE(S)

描述：来自色素性干皮病患者的细胞 (XP)在核苷酸切除修复(NER)的不同方面存在缺陷 除了XP变种(XP-V)个人，他们似乎有 正常的内尔。对XP-V最普遍接受的假设是它是 由于聚合酶相关基因的缺陷导致容易出错 病变旁路手术。首席研究员希望克隆XP-V基因 为了更好地了解这一缺陷的分子基础。证据 提出了与遗传有关的机制(S) 干皮病患者易患日光皮肤癌 色素性变异型(XP-V)患者，他们的临床特征是 经典的XP患者仍有正常的切除修复。他们的细胞是 对紫外线损伤的DNA复制异常缓慢，并且对 紫外线诱导的突变。已经获得的数据表明，这种极端的 超级可变性反映了有缺陷的、容易出错的复制复合体 产生紫外线诱导的突变的异常光谱。不仅是因为 完整细胞中的复制异常容易出错，但这也是事实 用于通过无细胞提取液体外复制辐照模板 来自XP-V细胞。它们代表了人类细胞中唯一已知的例子 一种缺陷的、容易出错的复制复合体，不是由缺陷的DNA引起的 修理。因此，它们提供了一个研究机制的机会。 正常细胞用来确保高保真的DNA复制。现建议： 同时使用两种方法克隆与该病有关的基因(S) XP-V细胞的异常特征及其基因特征 鉴定及其蛋白质产物。

DESCRIPTION: Cells from individuals with the disease Xeroderma pigmentosum (XP) are defective in different facets of nucleotide excision repair (NER) with the exception of XP-variant (XP-V) individuals, which appear to have normal NER. The most commonly accepted hypothesis for XP-V is that it is due to a defect in a polymerase-related gene that leads to error-prone bypass of lesions. The principal investigator wishes to clone the XP-V gene in order to better understand the molecular basis of this defect. Evidence is presented bearing on the mechanism(s) responsible for the genetic predisposition to sunlight-induced skin cancer found in xeroderma pigmentosum variant (XP-V) patients, who develop clinical features of classical XP patients yet have normal excision repair. Their cells are abnormally slow in replicating UV-damaged DNA and are extremely sensitive to UV-induced mutations. Data has been obtained that suggest that this extreme hypermutability reflects a defective, error-prone replication complex that yields an abnormal spectrum of UV-induced mutations. Not only is replication in the intact cells abnormally error-prone but this is also true for in vitro replication of an irradiated template by cell-free extracts from XP-V cells. They represent the only known example of human cells with a defective error-prone replication complex not resulting from defective DNA repair. Thus, they offer an opportunity to investigate the mechanisms normal cells use to insure high-fidelity DNA replication. It is proposed to use two approaches simultaneously to clone the gene(s) responsible for the abnormal characteristics of XP-V cells and then to characterize the gene identified and its protein product.