OsDMC1 Is Not Required for Homologous Pairing in Rice Meiosis
OsDMC1 Is Not Required for Homologous Pairing in Rice Meiosis
复制标题
水稻减数分裂中的同源配对不需要 OsDMC1。
DOI：
10.1104/pp.16.00167
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发表时间：
2016
期刊：
影响因子：
7.4
通讯作者：
Cheng Zhukuan
中科院分区：
文献类型：
--
作者：
Wang Hongjun;Hu Qing;Tang Ding;Liu Xiaofei;Du Guijie;Shen Yi;Li Yafei;Cheng Zhukuan
减数分裂同源重组是有性生殖的关键。DMC1是一种保守的重组酶，在减数分裂重组过程中参与引导同系物之间的单端侵袭。在本研究中，我们鉴定了水稻中与DMC1蛋白有很高序列相似性的两个紧密相关的蛋白质OsDMC1A和OsDMC1B。对Osdmc1a和Osdmc1b Tos17插入突变体的分析表明，这些基因在功能上是冗余的。免疫组织化学定位分析显示，OsDMC1病灶位于细线期，野生型小细胞粗线期晚期染色体消失。细胞学分析表明，Osdmc1a Osdmc1b双突变体完成了同源配对，但突触严重中断。Osdmc1a Osdmc1中二价体数目的减少和OsHEI10的异常位点最适合于OsDMC1在交叉形成中的重要作用。在没有OsDMC1的情况下，早期重组事件可能正常发生，导致γH2 AX、PAIR3、OsMRE11、OsCOM1和OsRAD51C的正常定位。此外，在配对缺陷突变体，如pair2、pair3、Oscom1和Osrad51c中未检测到OsDMC1，而OsDMC1被加载到减数分裂染色体上。综上所述，这些结果表明，在减数分裂过程中，OsDMC1对于水稻的同源配对是必不可少的，这与迄今在其他生物中发现的DMC1同源基因有很大的不同。
Meiotic homologous recombination is pivotal to sexual reproduction. DMC1, a conserved recombinase, is involved in directing single-end invasion between interhomologs during meiotic recombination. In this study, we identified OsDMC1A and OsDMC1B, two closely related proteins in rice (Oryza sativa) with high sequence similarity to DMC1 proteins from other species. Analysis ofOsdmc1aandOsdmc1b Tos17insertion mutants indicated that these genes are functionally redundant. Immunolocalization analysis revealed OsDMC1 foci occurred at leptotene, which disappeared from late pachytene chromosomes in wild-type meiocytes. According to cytological analyses, homologous pairing is accomplished in theOsdmc1a Osdmc1bdouble mutant, but synapsis is seriously disrupted. The reduced number of bivalents and abnormal OsHEI10 foci inOsdmc1a Osdmc1bestablishes an essential role for OsDMC1 in crossover formation. In the absence of OsDMC1, early recombination events probably occur normally, leading to normal localization of γH2AX, PAIR3, OsMRE11, OsCOM1, and OsRAD51C. Moreover, OsDMC1 was not detected in pairing-defective mutants, such aspair2,pair3,Oscom1, andOsrad51c, while it was loaded onto meiotic chromosomes inzep1,Osmer3,Oszip4, andOshei10. Taken together, these results suggest that during meiosis, OsDMC1 is dispensable for homologous pairing in rice, which is quite different from the DMC1 homologs identified so far in other organisms.