PRECLINICAL STUDIES OF ATAXIA-TELANGIECTASIA

AT领域一位成熟的高级研究员建议， 这有助于提高AT的诊断和治疗水平。该提案旨在 了解特定突变与临床 症状因为多达1%的普通人群可能携带 缺陷的ATM（A-T突变）基因，这些人可能会损害 也许是所有癌症患者的5%，希望这些研究将 还为AT携带者提供更好的诊断。ATM基因很大， 66个小外显子，从而提出了一个具有挑战性的技术问题， 突变筛查在加州大学洛杉矶分校，加蒂博士有一个独特的细胞库， 来自200多名A-T患者及其家属的mRNA和DNA。 这一资源使他在定位克隆中发挥了重要作用 这导致了1995年ATM基因的分离。从那时起， 已经确定了200种突变;其中一半以上来自 他的实验室。几乎所有这些突变都被检测到， 筛选mRNA/cDNA，使用蛋白质截短测试和构象 敏感凝胶电泳（CSGE）。加蒂博士将完成 定义cDNA缺陷及其相应的基因组（gDNA）突变， 其余的cDNA和他们的筛选DNA在另外100名患者， 没有cDNA的人。加蒂医生会用限制性内切酶 指纹识别、化学切割和半自动单链 构象多态性筛选方法。他还将参加 测试“智能芯片”和其他新推出的 筛选技术，以最大限度地减少实际测序量 来定义每一个突变。因为大多数病人都是复合型的 杂合子，他的资源应该允许400的表征 突变。加蒂博士还将确定每个受影响的单倍型 有耐心，只要有可能，每个家庭都有。然后他会比较 每种突变的类型和位点与患者的临床症状 来自多个受影响的家庭和族裔群体， 突变。将研究具有变异表型的家族。加蒂博士 预计他的研究项目最终将有助于定义 一种共同的生物学机制构成了这种复杂综合症的基础。 基于这种认识，他进而希望设计出一种理性的方法 对受影响儿童的有效治疗。

A well established and senior investigator in the field of AT has proposed this work to improve the diagnosis and treatment of AT. The proposal aims to understand the relationship between specific mutations and clinical symptoms. Because as many as 1% of the general population may carry a defective ATM (A-T mutated) gene, and these individuals may compromise perhaps 5% of all cancer patients, it is hoped that these studies will also offer better diagnosis for AT-carriers. The ATM gene is large, with 66 small exons, thereby presenting a challenging technical problem for mutation screening. At UCLA, Dr. Gatti has a unique repository of cells, mRNAs, and DNAs from greater than 200 A-T patients and their families. This resource allowed him to play a major role in the positional cloning that led to the isolation of the ATM gene in 1995. Since then greater than 200 mutations have been defined; more than half of these have come from his laboratory. Almost all of these mutations have been detected by screening mRNA/cDNA, using a protein truncation test and conformation sensitive gel electrophoresis (CSGE). Dr. Gatti will complete the task of defining cDNA defects and their corresponding genomic (gDNA) mutations on the remaining cDNAs and their screen DNA on 100 additional patients from whom cDNA is not available. Dr. Gatti will use restriction endonuclease finger printing, chemical cleavage, and semi-automated single strand conformational polymorphism screening methods. He will also participate in testing the efficiency of "smart chips" and other newly-introduced screening techniques in order to minimize the amount of actual sequencing necessary to define each mutation. Since most patients are compound heterozygotes, his resources should allow the characterization of 400 mutations. Dr. Gatti will also determine the affected haplotypes for each patient and, whenever possible, within each family. He will then compare the type and site of each mutation with the clinical symptoms of patients from multiple-affected families and ethnic groups with founder effect mutations. Families with variant phenotypes will be studied. Dr. Gatti anticipates that his research project will ultimately help to define the single common biological mechanism that underlies this complex syndrome. Based on this understanding, he then hopes to design a rational approach to an effective therapy of the affected children.