MOLECULAR DISSECTION OF THE WILLIAMS SYNDROME DELETION

描述(改编自《调查者摘要》)：威廉姆斯综合征 WS是一种发育障碍，伴有血管、结缔组织、内分泌 和中枢神经系统的表现。WS是由部分 涉及弹性蛋白基因的染色体带7q11.23的缺失 估计大小在1到3 Mb之间。表型的复杂性和 缺失的大小表明致病涉及邻近的 基因还没有确定。删除区域将以物理方式定义 通过脉冲场凝胶电泳法对YAC、P1代、 使用STS内容映射的PAC、BAC和COSMID克隆。亲和力捕捉， 外显子捕获、CpG岛克隆和cDNA文库筛选将用于 找出缺失的新基因。将确定功能域 根据数据库，序列同源性和表达模式将通过以下方式确定 Northern印迹和RT-PCR。新基因疑似起到调节作用 在发育中的作用或具有中枢神经系统或内分泌的作用 功能将有针对性地进行详细研究，包括获得 全长cdna序列和基因组结构，鉴定和定位 小鼠同源基因与胎儿组织和小鼠的原位杂交 胚胎。微缺失大小与临床的关系 将通过微卫星标记检测患者的表型 WS的变量表达式。顺式和反式调节效应 基因组上的缺失将通过表达研究进行调查 未缺失的等位基因和邻近基因。基因互作模型 要评估的包括多个基因丢失的相加效应， 远距离影响染色质结构的缺失和配子 印记。缺失形成的分子机制将是 调查过了。低拷贝数的假设在基因两侧重复 在减数分裂重组中的缺失区和易错性将是 通过克隆公共断点进行了测试。身份的识别 单倍体不足是WS表型的基础，它们之间的相互作用 以及对非缺失基因的影响，以及对潜在机制的检测 删除的形成将对新的 治疗方式以及对正常人类的洞察 发育过程。

DESCRIPTION (Adapted from the Investigator's Abstract): Williams syndrome (WS) is a developmental disorder with vascular, connective tissue, endocrine and central nervous system manifestations. WS is caused by a partial deletion of chromosome band 7q11.23 that involves the elastin gene and is estimated to be between 1 and 3 Mb in size. Complexity of the phenotype and size of the deletions suggest the pathogenetic involvement of contiguous genes yet to be identified. The deletion region will be physically defined by pulsed-field gel electrophoresis mapping and contig building of YAC, P1, PAC, BAC and cosmid clones using STS content mapping. Affinity capture, exon trapping, CpG island cloning and cDNA library screening will be used to identify new genes in the deletion. Functional domains will be identified by database sequence homology and expression patterns will be determined by Northern blotting and RT-PCR. Novel genes suspected of playing a regulatory role in development or of having a central nervous system or endocrine function will be targeted for detailed study, to include obtaining full-length cDNA sequence and genomic structure, identifying and mapping the mouse homologue and in situ hybridization on fetal tissues and mouse embryos. The relationship between size of the microdeletion and clinical phenotype will be examined by microsatellite marker testing of patients with variable expression of WS. Cis- and trans-acting regulatory effects of the deletion on the genome will be investigated through expression studies of the non-deleted alleles and neighboring genes. Models of gene interaction to be evaluated include additive effects of the loss of multiple genes, long-range effects on chromatin structure beyond the deletion, and gametic imprinting. The molecular mechanisms underlying deletion formation will be investigated. The hypothesis of low-copy number repeats flanking the deletion region and predisposing to errors in meiotic recombination will be tested through cloning of the common breakpoints. The identification of the genes whose haploinsufficiency underlies the WS phenotype, their interaction and effects on non-deleted genes, and detection of the mechanism underlying deletion formation will have implications for the development of new therapeutic modalities as well as provide insight into normal human developmental processes.