The dynamics of homologous chromosome pairing during male Drosophila meiosis
The dynamics of homologous chromosome pairing during male Drosophila meiosis
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DOI：
10.1016/s0960-9822(02)01090-4
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发表时间：
2002-09-03
期刊：
影响因子：
9.2
通讯作者：
Sedat, JW
中科院分区：
文献类型：
--
作者：
Vazquez, J;Belmont, AS;Sedat, JW
背景资料：减数分裂配对对于染色体在中期板上的正确定位以及随后在后期I的分离是必不可少的。在雄性黑腹果蝇中，减数分裂发生在没有重组或可识别的联会复合体（SC）的情况下。由于现有的细胞学技术的局限性，在雄性果蝇同源染色体配对的早期阶段还没有观察到，所涉及的机制知之甚少。结果：染色体标记GFP-Lac阻遏蛋白使我们能够跟踪，第一次，减数分裂染色体的行为在高分辨率，生活，在所有阶段的雄性果蝇减数分裂。同源染色体在精原细胞常染色质区和精母细胞发育早期配对。在第一次减数分裂前几个小时和G2/M转换前，同源体和姐妹染色单体沿着染色体臂的广泛分离发生在G2中期。另一方面，着丝粒显示出复杂的关联模式，特定的同源配对发生在G2中期。这些变化在染色体配对平行的变化，在大规模的染色体organization.Conclusions：我们的研究结果表明，广泛的相互作用沿着常染色质的启动，但不是维护，减数分裂配对的常染色体在雄性果蝇。我们建议，异染色质协会，或染色单体纠缠，可能是负责在G2后期的同源物协会的维护。我们的数据还表明，在精母细胞核中染色体领土的形成可能发挥积极的作用，在后期前期通过破坏非同源染色体之间的相互作用，以确保减数分裂配对的特异性。
Background: Meiotic pairing is essential for the proper orientation of chromosomes at the metaphase plate and their subsequent disjunction during anaphase I. In male Drosophila melanogaster, meiosis occurs in the absence of recombination or a recognizable synaptonemal complex (SC). Due to limitations in available cytological techniques, the early stages of homologous chromosome pairing in male Drosophila have not been observed, and the mechanisms involved are poorly understood.Results: Chromosome tagging with GFP-Lac repressor protein allowed us to track, for the first time, the behavior of meiotic chromosomes at high resolution, live, at all stages of male Drosophila meiosis. Homologous chromosomes pair throughout the euchromatic regions in spermatogonia and during the early phases of spermatocyte development. Extensive separation of homologs and sister chromatids along the chromosome arms occurs in mid-G2, several hours before the first meiotic division, and before the G2/M transition. Centromeres, on the other hand, show complex association patterns, with specific homolog pairing taking place in mid-G2. These changes in chromosome pairing parallel changes in large-scale chromosome organization.Conclusions: Our results suggest that widespread interactions along the euchromatin are required for the initiation, but not the maintenance, of meiotic pairing of autosomes in male Drosophila. We propose that heterochromatic associations, or chromatid entanglement, may be responsible for the maintenance of homolog association during late G2. Our data also suggest that the formation of chromosome territories in the spermatocyte nucleus may play an active role in ensuring the specificity of meiotic pairing in late prophase by disrupting interactions between nonhomologous chromosomes.