State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
New Phytol. 2019 Apr;222(2):805-819. doi: 10.1111/nph.15664. Epub 2019 Jan 25.
Meiotic recombination is closely linked with homologous pairing and synapsis. Previous studies have shown that HOMOLOGOUS PAIRING PROTEIN2 (HOP2), plays an essential role in homologous pairing and synapsis. However, the mechanism by which HOP2 regulates crossover (CO) formation has not been elucidated. Here, we show that OsHOP2 mediates the maturation of COs by promoting homologous pairing and synapsis in rice (Oryza sativa) meiosis. We used a combination of genetic analysis, immunolocalization and super-resolution imaging to analyze the function of OsHOP2 in rice meiosis. We showed that full-length pairing, synapsis and CO formation are disturbed in Oshop2 meiocytes. Moreover, structured illumination microscopy showed that OsHOP2 localized to chromatin and displayed considerable co-localization with axial elements (AEs) and central elements (CEs). Importantly, the interaction between OsHOP2 and a transverse filament protein of synaptonemal complex (ZEP1), provided further evidence that OsHOP2 was involved in assembly or stabilization of the structure of the synaptonemal complex (SC). Although the initiation of recombination and CO designation occur normally in Oshop2 mutants, mature COs were severely reduced, and human enhancer of invasion 10 (HEI10)10 foci were only present on the synapsed region. Putting the data together, we speculate that OsHOP2 may serve as a global regulator to coordinate homologous pairing, synapsis and meiotic recombination in rice meiosis.
减数分裂重组与同源配对和联会密切相关。先前的研究表明,同源配对蛋白 2(HOP2)在同源配对和联会中起着至关重要的作用。然而,HOP2 调节交叉(CO)形成的机制尚未阐明。在这里,我们表明 OsHOP2 通过促进同源配对和联会来介导 CO 的成熟,从而调节水稻(Oryza sativa)减数分裂中的 CO 形成。我们使用遗传分析、免疫定位和超分辨率成像相结合的方法来分析 OsHOP2 在水稻减数分裂中的功能。我们表明,全长配对、联会和 CO 形成在 Oshop2 减数分裂细胞中受到干扰。此外,结构照明显微镜显示 OsHOP2 定位于染色质上,并与轴丝元件(AE)和中央元件(CE)显示出相当大的共定位。重要的是,OsHOP2 与联会复合体(SC)的横丝蛋白 ZEP1 之间的相互作用进一步证明了 OsHOP2 参与了 SC 结构的组装或稳定。尽管在 Oshop2 突变体中,重组和 CO 标记的起始正常发生,但成熟的 CO 严重减少,并且人类入侵增强子 10(HEI10)10 焦点仅存在于联会区域。综合这些数据,我们推测 OsHOP2 可能作为一个全局调节剂,协调水稻减数分裂中的同源配对、联会和减数分裂重组。