Homologous recombination mechanisms in mammalian cells

哺乳动物细胞中的同源重组机制

• 批准号: 9923699
• 负责人: Maria Jasin
• 金额: $ 55.69万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-03 至 2020-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9923699
• 关键词: Address; Affect; Animals; Cells; Chromosomes; DNA; DNA Double Strand Break; DNA Repair; DNA lesion; Defect; Development; Double Strand Break Repair; Embryo; Excision; Fertility; Frequencies; Gene Conversion; Genes; Genetic Recombination; Genome; Genomics; Germ Cells; Goals; Homologous Gene; Human; Lead; Lesion; Longevity; Malignant Neoplasms; Malignant neoplasm of ovary; Mammalian Cell; Mammals; Mammary Neoplasms; Meiosis; Mismatch Repair; Mitotic; Mus; Mutation; Nucleotides; Outcome; Pattern; Play; Positioning Attribute; Process; Pseudoautosomal Region; Regulation; Resolution; Role; Sex Chromosomes; Somatic Cell; Spo11 protein; Spontaneous abortion; Sterility; Transact; Tumor Suppressor Proteins; ataxia telangiectasia mutated protein; homologous recombination; human disease; insight; interest; malignant breast neoplasm; ovarian neoplasm; public health relevance; repaired; segregation; tumor; tumorigenesis

 DESCRIPTION (provided by applicant): My lab has a long-standing interest in mechanisms and factors involved in homologous recombination (HR) in mammalian cells. We established that HR is a major repair mechanism in mammalian cells for DNA double-strand breaks (DSBs) and that breast and ovarian tumor suppressors are HR factors. In addition, we demonstrated with my colleague Scott Keeney that the mouse SPO11 protein introduces DSBs to initiate meiotic HR and that the non-Mendelian transfer of information - gene conversion - occurs during meiotic HR in the mouse. The importance of HR in somatic cells is particularly emphasized by the association of mutations in HR genes with human disease, especially cancer, while in germ cells, mistakes in HR can lead to miscarriage and developmental defects. The application builds on our earlier discoveries with the long-term goals of understanding HR mechanisms and factors in mitotic and meiotic cells. Our previous observations demonstrated that meiotic gene conversion occurs more broadly through meiotic HR hotspots than expected from relatively focused DSB formation, which has implications for the evolutionary longevity of hotspots. We will explore possible mechanisms that could lead to this pattern of gene conversion, focusing on the role of mismatch repair factors, as well as how sequence divergence affects HR frequency and outcomes. While HR between homologous chromosomes is critical in meiotic cells, it can be deleterious in mitotic cells if it leads to loss of heterozgosity. However, studies of mitotic interhomolog recombination have lagged behind those in meiotic cells. We will determine how mechanisms of meiotic and mitotic interhomolog HR compare and how the different cellular contexts impact DNA transactions. During meiosis, DSB numbers as well as position need to be tightly regulated. The ATM kinase plays a critical role in regulating meiotic DSB numbers; we will address whether ATM also controls the spatial regulation of DSB formation, including on the pseudoautosomal region shared by the sex chromosomes. Proper DSB repair by HR is critical in meiosis, as typically one to two crossovers occur on each homolog, with much of the remaining repair presumed to give rise to interhomolog noncrossovers. We will address whether loss of ATM leads to aberrant DSB repair outcomes. Many HR factors are crucial in mammals as their loss can lead to embryonic lethality, developmental defects, sterility, or tumorigenesis. We have begun to explore the function of additional presumptive HR factors and plan an integrated approach to understand the role of these factors in the animal in relation to that of known HR factors. Finally, the choice for a DSB to undergo HR or more mutagenic nonhomologous repair appears to be controlled at the initial end processing step, termed end resection. However, this process and its control are poorly understood in mammalian cells. We will develop nucleotide resolution end resection analysis to gain insight into this key control step.