State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Plant Cell. 2020 Apr;32(4):1323-1336. doi: 10.1105/tpc.19.00834. Epub 2020 Jan 29.
Meiosis consists of two highly conserved nuclear divisions, which allow eukaryotes to maintain their chromosome number through sexual reproduction. The successful completion of meiosis depends on homologous chromosome pairing. Centromere interactions during early meiotic prophase I facilitate homologous chromosome pairing, but the underlying mechanism is unclear. Here, we performed chromatin immunoprecipitation-mass spectrometry analysis of maize () anthers during early meiotic prophase I using anti-centromeric histone H3 (CENH3) antibodies and determined that the cohesin subunit Structural Maintenance of Chromosome3 (SMC3) interacts with CENH3 during this period. SMC3 is enriched at centromeres and along chromosome arms in threads from leptotene to pachytene and might promote interactions between homologous centromeres. We observed dysfunctional SMC3 assembly in meiotic-specific maize mutants with defective centromere pairing. In meiocytes, centromere pairing defects were observed during early meiotic prophase I, SMC3 was weakly associated with centromeres, and SMC3 did not localize to the chromosome arms. In wild-type mitosis, SMC3 is associated with chromatin and is enriched at centromeres from prophase to anaphase. CRISPR-Cas9-induced mutants showed premature loss of sister chromatid cohesion and mis-segregation of chromosomes in mitotic spreads. Our findings suggest that in addition to sister chromatid cohesion, ZmSMC3 participates in meiotic centromere pairing.
减数分裂由两个高度保守的核分裂组成，使真核生物能够通过有性繁殖维持其染色体数目。减数分裂的成功完成依赖于同源染色体配对。早期减数分裂前期 I 中的着丝粒相互作用促进同源染色体配对，但潜在的机制尚不清楚。在这里，我们使用抗着丝粒组蛋白 H3（CENH3）抗体对玉米（）花粉母细胞进行了早期减数分裂前期 I 的染色质免疫沉淀 - 质谱分析，结果表明结构维持染色体 3（SMC3）的着丝粒蛋白亚基在此期间与 CENH3 相互作用。SMC3 在从细线期到粗线期的线程中在着丝粒处和染色体臂上富集，并可能促进同源着丝粒之间的相互作用。我们观察到在有缺陷的中心体配对的减数分裂特异性玉米突变体中 SMC3 组装功能失调。在 减数分裂细胞中，在早期减数分裂前期 I 观察到着丝粒配对缺陷，SMC3 与着丝粒的结合较弱，并且 SMC3 不定位到染色体臂上。在野生型有丝分裂中，SMC3 与染色质相关，并且从前期到后期在着丝粒处富集。CRISPR-Cas9 诱导的 突变体在有丝分裂展开中显示出姐妹染色单体的过早丧失和染色体的错误分离。我们的研究结果表明，除了姐妹染色单体的凝聚外，ZmSMC3 还参与了减数分裂着丝粒配对。
