RADIATION INDUCTION OF GENOMIC REARRANGEMENTS IN YEAST

酵母基因组重排的辐射诱导

• 批准号: 6522366
• 负责人: MICHAEL Thomas FASULLO
• 金额: $ 20.93万
• 依托单位: ALBANY MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 2003-03-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6522366
• 关键词: DNA damage; DNA repair; DNA replication; Saccharomyces cerevisiae; artificial chromosomes; cell cycle; chromosome translocation; fungal genetics; gene deletion mutation; gene frequency; gene induction /repression; gene rearrangement; genetic crossing over; genetic polymorphism; genetic regulation; genetic strain; helicase; ionizing radiation; mutant; nucleic acid repetitive sequence; protein kinase; radiation genetics; recombinase; transposon /insertion element; ultraviolet radiation

DNA damage-induced cell cycle checkpoints have been postulated to be important in maintaining genetic stability by arresting or delaying the cell cycle to allow time for repair of recombinogenic DNA damage. Loss-of-function mutations that abolish checkpoints and increase genetic instability have been observed in cancer cells and may contribute to rapid proliferation and/or resistance to chemotherapeutic drugs and radiation therapy. Cell cycle checkpoint genes may function in a signal transduction pathway in which the presence of DNA damage is relayed to both the cell cycle machinery and the transcription apparatus to upregulate DNA repair genes. The purpose of this proposal is to elucidate the genetic pathway by which the Saccharomyces cerevisiae RAD9 checkpoint reduces genetic instability that results from homologous recombination between repeated sequences (ectopic recombination). We have previously described a chromosomal translocation assay that can measure genetic instability in yeast rad9 mutants. The first aim is to identify specific genes or combinations of genes in the RAD9- mediated signal transduction pathway which reduce the radiation- associated stimulation of translocations. The second aim is to examine the contribution of other cell cycle checkpoints in maintaining genetic stability. The third aim is to understand whether checkpoints also reduce the radiation-associated recombination between yeast Ty elements. The results obtained in this study may also elucidate current ideas concerning genomic stability in eukaryotic organisms: 1) that elevated levels of recombinases may be important in DNA repair of double-strand breaks (DSBs) generated by DNA replication, 2) that signal transduction pathways that trigger the G2-M checkpoint and control genetic stability are redundant, 3) that the non-random accumulation of genetic changes observed in checkpoint mutants may partially result from recombination between retrotransposons.

DNA损伤引起的细胞周期检查点已经假定对于通过阻止或延迟细胞周期以维修重组DNA损伤的时间来维持遗传稳定性很重要。 在癌细胞中观察到了废除检查点和增加遗传不稳定的功能丧失突变，并可能有助于快速增殖和/或对化学治疗药物和放射治疗的抗性。 细胞周期检查点基因可能在信号转导途径中起作用，在信号转导途径中，DNA损伤的存在与细胞周期机械和转录设备相关以上调DNA修复基因。 该建议的目的是阐明酿酒酵母RAD9检查点降低遗传不稳定的遗传途径，这是由于重复序列之间的同源重组（异位重组）引起的。 我们先前已经描述了一种可以测量酵母Rad9突变体中遗传不稳定性的染色体易位测定法。 第一个目的是在RAD9介导的信号转导途径中鉴定基因的特定基因或组合，从而减少辐射相关的易位刺激。 第二个目的是检查其他细胞周期检查点在维持遗传稳定性方面的贡献。 第三个目的是了解检查点是否还减少了酵母元素之间与辐射相关的重组。 在这项研究中获得的结果还可以阐明真核生物中基因组稳定性的当前思想：1）升高的重组酶水平升高在DNA修复DNA的双链断裂（DSB）（DSB）中可能很重要，DNA复制产生了信号转导途径的信号转导途径触发G2-M检查点和控制遗传稳定性是冗余的，3）在检查点突变体中观察到的非随机变化的非随机积累可能是由于逆转转座子之间的重组而部分导致的。