一个特异介导水稻减数分裂DSB形成基因的克隆与功能分析

减数分裂DNA双链的主动断裂(Double-Strand Break，DSB)与程序化修复过程，是实现遗传重组的过程，目前对这一最基本遗传学过程的认识还非常初步。我们鉴定到了一不育突变体，其减数分裂期同源染色体不配对，特异指示DSB形成的γH2AX抗体在突变体花粉母细胞染色体上检测不到免疫荧光信号，表明该突变体DSB形成存在缺陷。对该基因的精细定位和功能预测表明它与已报道的水稻DSB形成基因均不等位。本项目拟克隆该目的基因，制备目的蛋白多克隆抗体、利用qRT-PCR和免疫荧光染色反应等手段，研究目的基因在水稻不同组织的表达模式、其他减数分裂相关蛋白在突变体染色体上定位情况，初步研究目的基因与其它减数分裂相关基因的作用关系，解析目的基因参与DSB形成和同源重组的分子机制。

Meiosis is a critical process in eukaryotes that occupies a central role in the reproduction and life cycles of all sexually reproducing organisms. Meiosis differs from mitosis in that one round of DNA replication is followed by two sequential cell divisions, leading to the generation of four haploid cells from a single initial diploid cell. However, the mechanisms underlying meiosis remain largely obscure with respect to the series of events that occur in prophase I, including homologous chromosome recognition, pairing, synapsis and recombination. In the recent studies, we identified a rice mutant, which exhibits normal vegetative growth but complete male and female sterility. Cytological investigations revealed that homologous pairing and synapsis were severely disrupted in the mutant. No γH2AX signals in the mutant implied that double-strand break (DSB) formation was affected in the mutant meiocytes. In this proposal, we are going to identify the target gene by a map based cloning approach. We will also perform qRT-PCR and immunodetection to study its biological function in rice meiosis. According to the results of immunodetection, the biological functions of the target gene on homologous recombination would be investigated preliminarily. Together with the knowledge on the meiotic genes in rice isolated so far, those data will strength our understanding of the molecular mechanism on homologous recombination induced by DSB formation.