GERM CELLS--DNA REPAIR, MUTATION, & ENVIRONMENTAL AGENTS

生殖细胞——DNA 修复、突变、

• 批准号: 6345319
• 负责人: Christi A Walter
• 金额: $ 6.96万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-30 至 2002-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6345319
• 关键词: DNA repair; environmental health; gene mutation; gene targeting; genetically modified animals; laboratory mouse; male; radiation genetics; sperm

DESCRIPTION: Germline mutations can impact substantially on human health by having debilitating effects on ensuing offspring. It is estimated that 5% of liveborn offspring will have a genetic disorder. Of these, 20% are due to germline de novo mutations. From a genetic perspective, germ cells are profoundly different from somatic cells because they carry the DNA for the next generation of the organism, not simply for the next daughter cell. It seems logical to assume that safeguarding the integrity of germ- line DNA would provide survival advantages. Notably, testis has the lowest mutation frequency among tissues in lacI transgenic mice. Thus, it is reasonable to speculate that multiple safeguarding mechanisms may have evolved with this tissue type. An approach is presented to test the hypothesis that modulation of DNA repair pathways that are potentially important in determining spontaneous mutation frequencies in spermatogenic cells. First, various DNA repair activities will be assayed in cells at defined stages of spermatogenesis to identify DNA repair pathways that are potentially important in determining spontaneous mutation frequencies in spermatogenic cells. Based on these results, transgenic mice that have reduced activity in an appropriate pathway(s) will be made doubly transgenic by crossing with mice carrying the lacI transgene. lacI mutation frequencies will then be measured for specific spermatogenic cell types to confirm which DNA repair pathways play a fundamental role in determining spontaneous mutation frequencies. In the next phase, lacI and lacZ transgenic male mice will treated with an environmentally significant genotoxin, ionizing radiation. Subsequently mutation frequencies will be measured in discrete populations of spermatogenic cells to directly determine: 1) if there is a differential mutability among spermatogenic cells and 2) if mutation frequencies correlate with DNA repair activities measured in the first phase. This study will advance an understanding of the fundamental mechanisms involved in mutagenesis in germ cells.

描述：种系突变会对人类健康产生重大影响 对后代产生衰弱影响。估计 5% 的活产后代患有遗传性疾病。其中，20%是 由于种系从头突变。从遗传学的角度来看，生殖细胞 与体细胞有很大不同，因为它们携带 DNA 有机体的下一代，不仅仅是为了下一个女儿 细胞。假设保护细菌的完整性似乎是合乎逻辑的 线DNA将提供生存优势。值得注意的是，睾丸的含量最低。 lacI 转基因小鼠组织中的突变频率。因此，它是 有理由推测多种保护机制可能具有 与这种组织类型一起进化。提出了一种方法来测试 假设 DNA 修复途径的调节可能 对于确定生精自发突变频率很重要 细胞。首先，将在细胞中检测各种 DNA 修复活性 精子发生的定义阶段，以确定 DNA 修复途径 对于确定自发突变频率可能很重要 生精细胞。基于这些结果，转基因小鼠 适当途径中的活性减少将加倍 通过与携带 lacI 转基因的小鼠杂交进行转基因。内酰胺酶 然后将测量特定生精细胞的突变频率 类型来确认哪些 DNA 修复途径在 确定自发突变频率。在下一阶段，lacI 和 lacZ 转基因雄性小鼠将接受对环境具有重要意义的处理 基因毒素、电离辐射。随后的突变频率将为 在离散的生精细胞群中进行测量，以直接 确定： 1) 生精细胞之间是否存在差异突变 细胞和 2) 突变频率是否与 DNA 修复活动相关 在第一阶段测量。这项研究将增进对 生殖细胞诱变的基本机制。