Checkpoint protein interactions with a fragile site and chromosome instability

检查点蛋白与脆弱位点的相互作用和染色体不稳定性

• 批准号: 7148715
• 负责人: TED A. WEINERT
• 金额: $ 28.99万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7148715
• 关键词: DNA binding protein; DNA replication origin; Saccharomyces cerevisiae; chemical stability; chromosome translocation; chromosomes; fungal genetics; gene mutation; gene rearrangement; genetic regulation; microorganism culture; molecular dynamics; molecular site; nucleic acid denaturation; nucleic acid metabolism; nucleic acid sequence; nucleic acid structure; transfection; transfer RNA; yeasts

DESCRIPTION (provided by applicant): The overall goal of our research is to understand how checkpoint proteins regulate genome stability. We propose to study checkpoint proteins and instability arising at one chromosomal site that behaves like a fragile site. We found that the yeast fragile site behaves very much like a mammalian fragile site; both yeast and mammalian sites appear to stall replication forks, and both activate and are then stabilized by interaction with checkpoint proteins. We believe that study of the yeast fragile site provides a unique opportunity to understand mammalian fragile sites as well as to study events that link stalled replication forks to genome instability at many chromosomal sites. We have developed an experimental system to study this site, and believe its instability is due to stalling and breakage of DNA replication forks that is greatly enhanced in checkpoint mutants. Specifically, we propose that the initial event at this site is the stalling of DNA replication by tRNA genes. Second, we propose that the stalled forks collapse or break. Third, we propose that DNA breaks undergo non-allelic recombination with other chromosomal sites (that may also be fragile) to generate unstable translocations. Fourth, we propose the unstable translocation is unstable because it has a "hyperfragile" joint prone to additional rearrangements (cycles of instability). Finally, we propose that checkpoint and other regulatory proteins regulate fork stalling, breakage, and recombination to influence the sites instability. We believe that understanding each of these events at this site will be informative for understanding how such events occur at many sites in the genome. Completion of these studies will contribute to our understanding of how checkpoint proteins maintain genome stability. Checkpoints are cellular controls that ensure that chromosomes are correctly duplicated. Understanding how checkpoints keep a cell's genome intact is critical to understanding the process of how a normal cell becomes a cancer cell.

描述（由申请人提供）：我们研究的总体目标是了解检查点蛋白如何调节基因组稳定性。我们建议研究检查点蛋白和在一个表现得像脆弱位点的染色体位点上产生的不稳定性。我们发现酵母脆弱位点的行为与哺乳动物脆弱位点非常相似。酵母和哺乳动物位点似乎都会阻止复制叉，并且都激活并随后通过与检查点蛋白的相互作用而稳定。我们相信，对酵母脆弱位点的研究为了解哺乳动物脆弱位点以及研究将停滞的复制叉与许多染色体位点的基因组不稳定性联系起来的事件提供了独特的机会。我们开发了一个实验系统来研究这个位点，并相信它的不稳定性是由于 DNA 复制叉的停滞和断裂造成的，而检查点突变体中这种现象大大增强。具体来说，我们认为该位点的初始事件是 tRNA 基因导致的 DNA 复制停滞。其次，我们建议停滞的货叉崩溃或断裂。第三，我们提出DNA断裂与其他染色体位点（也可能是脆弱的）进行非等位基因重组，从而产生不稳定的易位。第四，我们认为不稳定易位是不稳定的，因为它有一个“超脆弱”关节，容易发生额外的重排（不稳定循环）。最后，我们提出检查点和其他调节蛋白调节叉停顿、断裂和重组以影响位点的稳定性。我们相信，了解该位点上的每个事件将为了解这些事件如何在基因组的许多位点上发生提供信息。这些研究的完成将有助于我们了解检查点蛋白如何维持基因组稳定性。检查点是确保染色体正确复制的细胞控制。了解检查点如何保持细胞基因组完整对于了解正常细胞如何变成癌细胞的过程至关重要。