Wicky C, Rose A M
University of British Columbia, Department of Medical Genetics, Vancouver, Canada.
Bioessays. 1996 Jun;18(6):447-52. doi: 10.1002/bies.950180606.
Chromosome ends have been implicated in the meiotic processes of the nematode Caenorhabditis elegans. Cytological observations have shown that chromosome ends attach to the nuclear membrane and adopt kinetochore functions. In this organism, centromeric activity is highly regulated, switching from multiple spindle attachments all along the chromosome during mitotic division to a single attachment during meiosis. C. elegans chromosomes are functionally monocentric during meiosis. Earlier genetic studies demonstrated that the terminal regions of the chromosomes are not equivalent in their meiotic potentials. There are asymmetries in the abilities of the ends to recombine when duplicated or deleted. In addition, mutations in single genes have been identified that mimic the meiotic effects of a terminal truncation of the X chromosome. The recent cloning and characterization of the C. elegans telomeres has provided a starting point for the study of chromosomal elements mediating the meiotic process.
染色体末端与线虫秀丽隐杆线虫的减数分裂过程有关。细胞学观察表明,染色体末端附着于核膜并行使动粒功能。在这种生物中,着丝粒活性受到高度调控,在有丝分裂期间从沿着染色体的多个纺锤体附着转变为减数分裂期间的单个附着。秀丽隐杆线虫的染色体在减数分裂期间功能上是单着丝粒的。早期的遗传学研究表明,染色体的末端区域在减数分裂潜能方面并不等同。当复制或缺失时,末端的重组能力存在不对称性。此外,已经鉴定出单个基因突变,这些突变模拟了X染色体末端截短的减数分裂效应。秀丽隐杆线虫端粒的近期克隆和表征为研究介导减数分裂过程的染色体元件提供了一个起点。