Alsheimer M
Department of Cell and Developmental Biology, Biocenter of the University of Würzburg, Würzburg, Germany.
Genome Dyn. 2009;5:81-93. doi: 10.1159/000166621.
Segregation of the homologous chromosomes is the most important feature of meiosis as it ensures the faithful haploidization of the genome. It essentially depends on an accurate prearrangement of chromosomes that culminates in a precise and unambiguous pairing of the homologs, which in turn is a prere - quisite for their correct segregation. Pairing with the right partner is accompanied by, moreover it implicitly requires characteristic chromosomal movements that, remarkably, appear to be driven by the chromosomal ends. In prophase I, telomeres firmly attach to the nuclear envelope and move to congregate in a small cluster, thus trailing homologs into close vicinity, a condition that was suggested to promote homolog recognition and alignment. The evolutionarily highly conserved phenomenon of the telomere driven meiotic chromosome rearrangement is yet known for a long time, but the molecular mechanisms responsible for telomere attachment and their directed movements have remained largely unknown. However, in the recent years significant progress has been made in this issue, which has provided some novel clues about the molecular requirements and function of the characteristic meiotic telomere dynamics.
同源染色体的分离是减数分裂最重要的特征,因为它确保了基因组准确地单倍体化。这主要依赖于染色体的精确预先排列,最终导致同源染色体精确且明确地配对,而这反过来又是它们正确分离的先决条件。与正确的伙伴配对还伴随着,而且隐含地需要特定的染色体运动,值得注意的是,这些运动似乎是由染色体末端驱动的。在减数第一次分裂前期,端粒牢固地附着在核膜上并移动聚集在一个小簇中,从而将同源染色体拖到附近,这种情况被认为有助于同源染色体的识别和排列。端粒驱动的减数分裂染色体重排这一在进化上高度保守的现象早已为人所知,但负责端粒附着及其定向运动的分子机制在很大程度上仍然未知。然而,近年来在这个问题上取得了重大进展,这为减数分裂端粒特征性动态变化的分子要求和功能提供了一些新线索。