Synapsis and chiasma formation in Caenorhabditis elegans require HIM-3, a meiotic chromosome core component that functions in chromosome segregation.
Synapsis and chiasma formation in Caenorhabditis elegans require HIM-3, a meiotic chromosome core component that functions in chromosome segregation.
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DOI：
10.1101/gad.13.17.2258
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发表时间：
1999-09
影响因子：
10.5
通讯作者：
M. Zetka;I. Kawasaki;S. Strome;F. Müller
中科院分区：
文献类型：
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作者：
M. Zetka;I. Kawasaki;S. Strome;F. Müller
减数分裂染色体围绕在复制的姐妹染色单体之间形成的蛋白质核心组织。我们已经分离出一个秀丽隐杆线虫基因，他-3，它编码的染色体核心减数分裂特异性组件与一些相似的酵母侧元件蛋白Hop 1 p。针对HIM-3产生的抗体将该蛋白定位于早期前期I中的凝聚染色体以及突触和去突触染色体的核心。在RNA干扰实验中，染色体似乎在没有可检测到的蛋白质的情况下正常地凝聚，但不能突触和形成交叉，这表明HIM-3对这些过程是必不可少的。HIM-3的亚型，虽然是突触精通，显示交换的频率严重降低，表明HIM-3在建立正常水平的同源物交换中具有作用。HIM-3突变体也显示出减数分裂染色体分离的缺陷，并且蛋白质在染色体核心的持续存在直到中期I-后期I过渡，这表明HIM-3可能在姐妹染色单体凝聚中发挥作用。对him-3的分析提供了多细胞生物中染色体核心成分的第一个功能描述，并表明在突触和重组的早期减数分裂事件与后来的事件（如分离）之间存在机械联系。
Meiotic chromosomes are organized about a proteinaceous core that forms between replicated sister chromatids. We have isolated a Caenorhabditis elegans gene, him-3, which encodes a meiosis-specific component of chromosome cores with some similarity to the yeast lateral element protein Hop1p. Antibodies raised against HIM-3 localize the protein to condensing chromosomes in early prophase I and to the cores of both synapsed and desynapsed chromosomes. In RNA interference experiments, chromosomes appear to condense normally in the absence of detectable protein but fail to synapse and form chiasmata, indicating that HIM-3 is essential for these processes. Hypomorphs of him-3, although being synapsis proficient, show severe reductions in the frequency of crossing-over, demonstrating that HIM-3 has a role in establishing normal levels of interhomolog exchange. Him-3 mutants also show defects in meiotic chromosome segregation and the persistence of the protein at the chromosome core until the metaphase I-anaphase I transition suggests that HIM-3 may play a role in sister chromatid cohesion. The analysis of him-3 provides the first functional description of a chromosome core component in a multicellular organism and suggests that a mechanistic link exists between the early meiotic events of synapsis and recombination, and later events such as segregation.