Segregation of holocentric chromosomes at meiosis in the nematode, Caenorhabditis elegans
Segregation of holocentric chromosomes at meiosis in the nematode, Caenorhabditis elegans
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DOI：
10.1007/bf00710603
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发表时间：
1993-05-01
影响因子：
2.6
通讯作者：
Thomson, J. Nichol
中科院分区：
文献类型：
--
作者：
Albertson, Donna G.;Thomson, J. Nichol
本文描述了秀丽隐杆线虫（Caelophabditiselegans）全着丝粒染色体在精子发生和卵子发生过程中的减数分裂分离。有丝分裂染色体典型的扩展动粒不能在减数分裂二价体上区分;相反，微管似乎突出到染色质中。精子发生过程中形成的纺锤体含有中心粒和星形细胞，而卵子发生过程中纺锤体呈无中心柱和桶形。用抗微管蛋白免疫荧光法研究了无中心纺锤体的形成。微管阵列被认为是第一次积累在附近的减数分裂染色体之前，大会。在后期，观察到平行于胚胎表面的长达13 μ的细长纺锤体结构。纺锤体的进一步发展似乎涉及其缩短成桶形和旋转，使一个纺锤体极是对着膜。到后期，极间纺锤体长度达到最小3-4亩。通过探针DNA原位杂交标记减数分裂二价体中每个染色单体的一端，以表明在卵子发生中，染色单体在二价体中是端对端相连的。此外，同源物的右端或左端都可以结合在一起。在中期I的二价体轴向取向，这样的动力学活动被限制在每对姐妹染色单体的一端。在中期II，染色体也轴向排列。
The meiotic segregation of the holocentric chromosomes of Caenorhabditis elegans in both spermatogenesis and oogenesis is described. The extended kinetochore typical of the mitotic chromosome could not be differentiated on meiotic bivalents; instead microtubules appeared to project into the chromatin. The meiotic spindles formed during spermatogenesis contain centrioles and asters, while in oogenesis the spindles are acentriolar and barrel shaped. The formation of the acentriolar spindle was studied in fixed specimens by anti-tubulin immunofluorescence. Microtubule arrays were seen first to accumulate in the vicinity of the meiotic chromosomes prior to congression. At later stages, elongated spindle structures up to 13 mu in length were observed parallel to the surface of the embryo. Further development of the spindle appeared to involve its shortening into a barrel shape and rotation so that one spindle pole was opposed to the membrane. By anaphase the pole-to-pole spindle length reached a minimum of 3-4 mu. One end of each chromatid in the meiotic bivalent was labelled by in situ hybridization of a probe DNA to show that in oogenesis the chromatids were associated end-to-end in the bivalent. Furthermore, either the right or the left ends of the homologues could be held in association. At metaphase I the bivalents were oriented axially, such that kinetic activity was restricted to one end of each pair of sister chromatids. At metaphase II the chromosomes were also aligned axially.