Genetic and biochemical analysis of Drosophila MEI-9

果蝇 MEI-9 的遗传和生化分析

• 批准号: 6551673
• 负责人: HUTTON M KEARNEY
• 金额: $ 3.83万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6551673
• 关键词: DNA repair; Drosophilidae; arthropod genetics; chemical stability; chromosome movement; endonuclease; gene mutation; genetic crossing over; meiosis; postdoctoral investigator; DNA repair; Drosophilidae; arthropod genetics; chemical stability; chromosome movement; endonuclease; gene mutation; genetic crossing over; meiosis; postdoctoral investigator

The failure to resolve meiotic intermediates as crossovers results in high levels of chromosome non-disjunction leading to sterility or inviable progeny. Many of the molecular details have been described for early events in meiotic recombination, but resolution of recombination intermediates into crossover (or non-crossover) products remains to be defined. Mutations in Drosophila mei-9 result in a dramatic decrease in meiotic crossovers and failure to repair mismatched DNA in recombination intermediates. mei-9 encodes a nuclease required for nucleotide excision repair (NER), and mutations in the human homologue of mei-9, XPF are associated with cancer predisposition. While the role of the MEI-9 endonuclease in NER is well understood, its function in meiosis remains unclear. Described herein is the proposal that meiotic Holliday junctions are cleaved by the MEI-9 endonuclease and that this cleavage is necessary for efficient resolution as a crossover. Additionally, it is suggested that the nicks introduced by MEI-9-dependent cleavage of Holliday junctions serve as an entry point for exonucleases to effect repair of mismatches in meiotic intermediates. This model allows one to make testable predictions about the arrangement of recombinant DNA on meiotic chromosomes. Molecular analysis will be performed on meiotic chromosomes derived from wild-type and mei-9 files. In addition, purified MEI-9 protein (and associated proteins) will be analyzed in vitro for the ability to cleave Holliday junctions.

由于交叉导致高水平的染色体非分离导致不育或不可或缺的后代，因此无法解析减数分裂中间体。为减数分裂重组的早期事件描述了许多分子细节，但是将重组中间体分辨到跨界（或非交叉）产物中仍然有待定义。果蝇MEI-9的突变导致减数分裂跨界的急剧下降，并且在重组中间体中无法修复不匹配的DNA。 MEI-9编码核苷酸切除修复（NER）所需的核酸酶，MEI-9，XPF的人类同源物中的突变与癌症易感性有关。虽然MEI-9核酸内切酶在NER中的作用已被充分了解，但其在减数分裂中的功能尚不清楚。本文描述的是，MEI-9核酸内切酶裂解减数分裂的霍利迪连接，并且这种分裂对于有效分辨率作为交叉是必要的。此外，建议通过MEI-9依赖性裂缝引入的霍利迪连接处引入的划痕是外核酸外导核的切入点，以实现减数分裂中间体中不匹配的修复。该模型允许人们对重组DNA在减数分裂染色体上的排列进行可检验的预测。分子分析将对从野生型和MEI-9文件得出的减数分裂染色体进行。此外，将在体外分析纯化​​的MEI-9蛋白（及相关蛋白），以裂解霍利迪连接的能力。