In vivo mutation assay based on pig-a locus

基于pig-a基因座的体内突变测定

• 批准号: 6841023
• 负责人: STEPHEN D DERTINGER
• 金额: $ 9.25万
• 依托单位: LITRON LABORATORIES, LTD.
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-13 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6841023
• 关键词: biotechnology; diagnosis design /evaluation; diagnostic tests; dimethylbenzanthracene; erythrocytes; flow cytometry; gene mutation; glycosylphosphatidylinositols; laboratory rat; mutagen testing; nitrosourea; rapid diagnosis; tissue /cell culture

DESCRIPTION (provided by applicant): Mutation to DNA is a primary mechanism by which cancers arise. These events have also been implicated in diseases such as atherosclerosis, and processes such as aging. Therefore, there is an important need for sensitive methods which are capable of identifying chemical or physical agents that can mutate DNA. Methods for measuring in vivo mutation currently exist, each with advantages and limitations. While some are based on colony formation and require tissue culture work, others rely on proprietary rodents. The in vivo mutation assay that is proposed herein is based on the pig-a locus. The pig-a gene product is essential for the biosynthesis of glycosyl-phosphatidylinositol (GPI) anchors. Mutations giving rise to non-functional GPI anchors prevent certain proteins from being expressed on the cell surface, and this represents a phenotype which can be measured by high speed flow cytometry. Importantly, harvested cells are not cultured before analysis, thus the need for costly- and labor-intensive tissue culture work is eliminated. Furthermore, since pig-a is an endogenous gene located on the X-chromosome, it is likely that this mutation scoring system will be applicable to any mammalian species of toxicologic interest. Phase I experiments will focus on evaluating the feasibility of enumerating in vivo pig-a mutation with a single-laser flow cytometer. The animal model for these initial investigations is the Sprague-Dawley rat, and the target cells will be peripheral blood erythrocytes. Blood from vehicle control and genotoxicant-treated animals will be used in Phase I to identify fluorescent staining techniques which provide for resolution of GPI-competent and GPI-deficient erythrocytes, and also to assess experimental parameters such as cell harvest time.

描述（由申请人提供）： DNA突变是癌症产生的主要机制。这些事件也与动脉粥样硬化等疾病和衰老等过程有关。因此，非常需要能够鉴定能够使DNA突变的化学或物理试剂的敏感方法。目前存在用于测量体内突变的方法，每种方法都具有优点和局限性。虽然有些基于菌落形成并需要组织培养工作，但其他依赖于专有啮齿动物。本文提出的体内突变测定基于pig-a基因座。pig-a基因产物对于糖基-磷脂酰肌醇（GPI）锚的生物合成是必需的。产生非功能性GPI锚的突变阻止某些蛋白质在细胞表面上表达，这代表了可以通过高速流式细胞术测量的表型。重要的是，收获的细胞在分析前不进行培养，因此消除了对昂贵和劳动密集型组织培养工作的需求。此外，由于pig-a是位于X染色体上的内源性基因，因此该突变评分系统可能适用于任何毒理学关注的哺乳动物种属。第一阶段的实验将集中在评估的可行性，在体内计数猪突变与单激光流式细胞仪。这些初步研究的动物模型是Sprague-Dawley大鼠，靶细胞是外周血红细胞。溶剂对照和遗传毒性剂处理动物的血液将用于I期研究，以确定用于分离GPI活性红细胞和GPI缺陷红细胞的荧光染色技术，并评估实验参数，如细胞收获时间。