Wang Chong, Higgins James D, He Yi, Lu Pingli, Zhang Dabing, Liang Wanqi
Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 20040, China (C.W., Y.H., D.Z., W.L.).
Department of Genetics, University of Leicester, Leicester LE1 7RH, United Kingdom (J.D.H.).
Plant Physiol. 2017 Feb;173(2):1316-1329. doi: 10.1104/pp.16.01726. Epub 2017 Jan 3.
Yen1/GEN1 are canonical Holliday junction resolvases that belong to the RAD2/XPG family. In eukaryotes, such as budding yeast, mice, worms, and humans, Yen1/GEN1 work together with Mus81-Mms4/MUS81-EME1 and Slx1-Slx4/SLX1-SLX4 in DNA repair by homologous recombination to maintain genome stability. In plants, the biological function of Yen1/GEN1 remains largely unclear. In this study, we characterized the loss of function mutants of OsGEN1 and OsSEND1, a pair of paralogs of Yen1/GEN1 in rice (Oryza sativa). We first investigated the role of OsGEN1 during meiosis and found a reduction in chiasma frequency by ∼6% in osgen1 mutants, compared to the wild type, suggesting a possible involvement of OsGEN1 in the formation of crossovers. Postmeiosis, OsGEN1 foci were detected in wild-type microspore nuclei, but not in the osgen1 mutant concomitant with an increase in double-strand breaks. Persistent double-strand breaks led to programmed cell death of the male gametes and complete male sterility. In contrast, depletion of OsSEND1 had no effects on plant development and did not enhance osgen1 defects. Our results indicate that OsGEN1 is essential for homologous recombinational DNA repair at two stages of microsporogenesis in rice.
Yen1/GEN1是属于RAD2/XPG家族的典型霍利迪连接体解离酶。在真核生物中，如芽殖酵母、小鼠、线虫和人类，Yen1/GEN1与Mus81-Mms4/MUS81-EME1以及Slx1-Slx4/SLX1-SLX4共同参与同源重组DNA修复，以维持基因组稳定性。在植物中，Yen1/GEN1的生物学功能仍 largely不清楚。在本研究中，我们对水稻（Oryza sativa）中Yen1/GEN1的一对旁系同源基因OsGEN1和OsSEND1的功能缺失突变体进行了表征。我们首先研究了OsGEN1在减数分裂过程中的作用，发现与野生型相比，osgen1突变体的交叉频率降低了约6%，这表明OsGEN1可能参与了交叉的形成。减数分裂后，在野生型小孢子核中检测到OsGEN1焦点，但在osgen1突变体中未检测到，同时双链断裂增加。持续的双链断裂导致雄配子程序性细胞死亡和完全雄性不育。相比之下，OsSEND1的缺失对植物发育没有影响，也没有加剧osgen1的缺陷。我们的结果表明，OsGEN1在水稻小孢子发生的两个阶段对同源重组DNA修复至关重要。
