Mechanisms and regulation of meiotic recombination"

减数分裂重组机制及调控"

• 批准号: 10313233
• 负责人: Carolyn Anne Turcotte
• 金额: $ 3.71万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10313233
• 关键词: Age; Aging; Aneuploidy; Biological Assay; Chromosome Segregation; Chromosomes; Cleaved cell; Computer Models; Congenital chromosomal disease; Cruciform DNA; DNA; DNA Double Strand Break; Data; Defect; Down Syndrome; Drosophila genus; Drosophila melanogaster; Elements; Ensure; Failure; Frequencies; Genes; Genetic; Genetic Nondisjunction; Genetic Recombination; Genome; Genomics; Germ Cells; Haploidy; Heteroduplex Analysis; Heteroduplex DNA; Homologous Gene; Human; Incidence; Infertility; Light; Link; Location; Malignant Neoplasms; Maps; Maternal Age; Meiosis; Meiotic Recombination; Methodology; Modeling; Mutation; Oocytes; Organism; Output; Ovulation; Pathway interactions; Pattern; Phenotype; Process; Proteins; Recombinants; Regulation; Risk; Sister Chromatid; Site; Spontaneous abortion; Structure; Techniques; Testing; age related; base; cohesion; ds-DNA; experimental study; genome sequencing; genome-wide; homologous recombination; in silico; in vivo; insight; mathematical model; models and simulation; mutant; predictive modeling; prevent; repaired; segregation; simulation; tool; whole genome

Project Summary/Abstract Meiosis is a tightly regulated process that ensures formation of haploid gametes. Failure to segregate homologous chromosomes during meiosis results in aneuploidy, leading to chromosomal disorders such as Down syndrome and miscarriage. Incidences of homolog nondisjunction increase with oocyte age. A hypothesized cause of age-related nondisjunction is that aging oocytes are unable to maintain chiasmata, physical linkages between homologs, until they are ovulated. Chiasmata are formed via crossovers, genetic exchanges between homologs that are formed by repairing double-strand DNA breaks via homologous recombination. To ensure proper homolog segregation, the number and spatial patterning of crossovers is tightly regulated in a phenomenon known as “crossover patterning.” Understanding regulation of crossover formation and patterning, and therefore homologous recombination mechanism, is integral to combatting age-related infertility. Pathway choices within homologous recombination are traceable in products via heteroduplex DNA (hDNA), DNA in which the strands come from different parental chromosomes. The classic meiotic HR model indicates that a crossover is formed via a double Holliday junction (dHJ), a structure in which two DNA molecules are linked via criss-crossing of their strands at two adjacent sites. In this classic model, ligated dHJs give rise to all crossovers by being cleaved in one of two patterns, generating two possible hDNA signatures. The model predicts that both patterns are equally likely, yet only one of the hDNA signatures has been observed. This hDNA signature bias demands revision of the meiotic recombination model. Our lab has mapped hDNA at recombinants of a test locus in Drosophila melanogaster, but redefining the meiotic recombination model requires much more extensive analysis of hDNA than is possible with this methodology. To overcome this obstacle, I will pioneer “hetSeq”, a whole-genome sequencing technique to detect hDNA from meiotic products, to continue redefining this model. A further gap in our understanding of crossover regulation is that although crossover patterning has been observed since the early 1900s, its relationship to homologous recombination mechanism remains unclear. Many meiotic proteins have a known function in homologous recombination, and their depletion leads to crossover patterning defects. I am developing a mathematical model of recombination to test hypotheses about these proteins. To do this, I will alter aspects of crossover patterning within the model and compare the output to previously obtained experimental data from mutants lacking these proteins. I am additionally using this model to develop a simulation of recombination using whole- genome sequencing data. The proposed experiments will strengthen understanding of crossover regulation to provide guidance in combatting age-related infertility and aneuploidy.

项目摘要/摘要 减数分裂是一个严格调节的过程，可确保形成单倍体游戏。不隔离 减数分裂过程中的同源染色体导致非整倍性，导致染色体疾病 例如唐氏综合症和流产。同源性非分离的发生率随卵母细胞的增加而增加 与年龄相关的非分离的假设原因是，老化的卵母细胞无法维持chiasmata， 同源物之间的物理联系，直到排卵为止。 Chiasmata是通过跨界的通用形成的 通过同源物修复双链DNA断裂而形成的同源物之间的交流 重组。为了确保适当的同源分离，跨界的数量和空间图案紧密 以一种被称为“交叉图案”的现象进行调节。了解跨界形成的调节 图案，因此是同源重组机制，是对抗年龄相关的不可或缺的 不育。同源重组中的途径选择在产品中可以通过杂化DNA追溯 （HDNA），链来自不同亲本染色体的DNA。经典的减数分裂人力资源模型 表明通过双Holliday连接（DHJ）形成交叉，该结构有两个DNA分子 通过在两个相邻地点的链条纵横交道链接。在这个经典模型中，连接的DHJ产生 通过以两种模式之一裂解，产生两个可能的HDNA签名，所有交叉。模型 预测这两种模式都可能同样可能，但仅观察到了HDNA特征中的一个。这 HDNA签名偏见需要修订减数分裂重组模型。我们的实验室已映射HDNA 果蝇中的测试基因座的重组者，但重新定义了减数分裂重组模型 与此方法相比，对HDNA的分析需要更广泛的分析。克服这一点 障碍，我将开拓“ Hetseq”，这是一种全基因组测序技术，可从减数分裂中检测HDNA 产品，继续重新定义此模型。我们对跨界法规的理解的另一个差距是 尽管自1900年代初以来就已经观察到了跨界图案，但它与同源的关系 重组机制尚不清楚。许多减数分裂蛋白在同源方面具有已知功能 重组及其部署会导致交叉模式缺陷。我正在发展数学 重组模型以检验有关这些蛋白质的假设。为此，我将改变跨界的各个方面 在模型中构图并将输出与先前从突变体获得的实验数据进行比较 缺乏这些蛋白质。我还使用此模型来使用整个 - 基因组测序数据。提出的实验将加强对跨界的理解 调节以应对与年龄相关的不育症和非整倍性的指导。