Ding Da-Qiao, Yamamoto Ayumu, Haraguchi Tokuko, Hiraoka Yasushi
CREST Research Project, Kansai Advanced Research Center, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan.
Dev Cell. 2004 Mar;6(3):329-41. doi: 10.1016/s1534-5807(04)00059-0.
Pairing of homologous chromosomes is important for homologous recombination and correct chromosome segregation during meiosis. It has been proposed that telomere clustering, nuclear oscillation, and recombination during meiotic prophase facilitate homologous chromosome pairing in fission yeast. Here we examined the contributions of these chromosomal events to homologous chromosome pairing, by directly observing the dynamics of chromosomal loci in living cells of fission yeast. Homologous loci exhibited a dynamic process of association and dissociation during the time course of meiotic prophase. Lack of nuclear oscillation reduced association frequency for both centromeric and arm regions of the chromosome. Lack of telomere clustering or recombination reduced association frequency at arm regions, but not significantly at centromeric regions. Our results indicate that homologous chromosomes are spatially aligned by oscillation of telomere-bundled chromosomes and physically linked by recombination at chromosome arm regions; this recombination is not required for association of homologous centromeres.
同源染色体配对对于减数分裂过程中的同源重组和正确的染色体分离很重要。有人提出，减数分裂前期的端粒聚集、核振荡和重组有助于裂殖酵母中的同源染色体配对。在这里，我们通过直接观察裂殖酵母活细胞中染色体位点的动态，研究了这些染色体事件对同源染色体配对的贡献。在减数分裂前期的时间进程中，同源位点表现出一个动态的关联和解离过程。缺乏核振荡会降低染色体着丝粒和臂区域的关联频率。缺乏端粒聚集或重组会降低臂区域的关联频率，但着丝粒区域的关联频率没有显著降低。我们的结果表明，同源染色体通过端粒捆绑染色体的振荡在空间上排列，并在染色体臂区域通过重组物理连接；同源着丝粒的关联不需要这种重组。
