Molecular Genetics of X-linked Cataracts

描述（由申请人提供）：先天性白内障，临床定义 白内障的存在是基因突变的结果， 这是正确的透镜发展所需要的。本研究的主要目的 一项计划是鉴定人类X染色体连锁白内障的基因缺陷 牙齿（XLCD）综合征，一种与先天性白内障相关的类型， 小角膜和牙齿畸形根据X染色体上的表型和位置 染色体，Xcat小鼠是人类XLCD的最佳动物模型。我们有 通过种间回交定位Xcat，并确定了两个 标记Dx Was 31和DxPas 18显示不与Xcat重组。酵母 人工染色体（YAC）和细菌人工染色体（BAC）文库 用这些标记筛选，以开发Xcat的900kb重叠群图谱 关键区域。Xcat临界区域将通过BAC进行细化 转基因互补实验旨在鉴定一种 含有Xcat基因我们将获得这个BAC的序列并对其进行分析 筛选潜在的转录单位和前候选Xcat基因 在透镜中的表达，并通过南方动物园印迹和数据库搜索 跨物种保护保守和表达的候选基因 将评估产前透镜中的表达。他们还将 评估Xcat cDNA中的突变。突变体与 Xcat基因和白内障表型将通过靶向破坏来证实 Xcat在转基因动物中的作用。最后，正常的小鼠Xcat序列将是 用于克隆相应的正常人类基因。确定后 正常XLCD基因的结构，XLCD患者将进行检查，以确定 如果Xcat人类同源物中存在突变。识别XLCD基因 将有助于我们理解参与透镜的分子事件 发展

DESCRIPTION (provided by applicant): Congenital cataracts, clinically defined as the presence of cataracts at birth, are the result of mutations in genes that are required for proper lens development. The primary objective of this proposal is to identify the gene defective in the human X-linked cataract dental (XLCD) syndrome, a type of congenital cataract associated with microcornea and dental anomalies. Based on phenotype and location on the X chromosome, the Xcat mouse is the best animal model for human XLCD. We have positionally mapped Xcat through an interspecific backcross and identified two markers Dx Was3 I and DxPas18 that show no recombination with Xcat. Yeast artificial chromosome (YAC) and bacterial artificial chromosome (BAC) libraries were screened with these markers to develop a 900kb contig map of the Xcat critical region. The Xcat critical region will be refined through BAC transgenic complementation experiments designed to identify a single BAC that contains the Xcat gene. We will obtain the sequence of this BAC and analyze it for potential transcription units and ex Candidate Xcat genes will be screened for expression in the lens and by Southern zoo blots and database searches for conservation across species. Candidate genes that are conserved and expressed in prenatal lens will be evaluated for expression in Xcat mice. They will also be evaluated for mutations in the Xcat cDNA. The correlation between the mutant Xcat gene and the cataract phenotype will be confirmed by targeted disruption of Xcat in transgenic animals. Finally, the normal mouse Xcat sequence will be used to clone the corresponding normal human gene. After determining the structure of the normal XLCD gene, XLCD patients will be examined to determine if mutations in the Xcat human homolog are present. Identifying the XLCD gene would contribute to our understanding of the molecular events involved in lens development.