摘要
染色体精确分离是在纺锤体的正确组装和纺锤体检查点(spindle assembly checkpoint,SAC)的监控下完成的,对于哺乳动物卵母细胞来说,纺锤体的形成和SAC都是保证染色体精确分离的重要因素,如果染色体分离错误将直接导致自发性流产或其他出生缺陷。卵母细胞中心体缺失后,细胞依然能够依靠独立于中心体而围绕染色体成核的微管反向平行排列能形成双极纺锤体,即自我组装纺锤体。由微观组织中心(microtubue organizing center,MTOC)召集微管聚集,成熟促进因子(maturation promoting factor,MPF)维持两次减数分裂过程中纺锤体的形成过程,细胞静止因子(cytostatic factor,CSF)维持分裂中期结构,使纺锤体在染色体没有全部集合到赤道板时保持稳定。大体积的卵母细胞容易产生非整倍体,且卵母细胞中不含有中心体这一特殊性导致卵母细胞中是否存在SAC在很长一段时间内存在争议,但现在SAC是确保卵母细胞染色体精确分离的机制之一已被初步证明。在减数分裂中期染色体之间存在一种黏连,细胞会产生"等待-后期"信号抑制SAC活性,从而保持这种黏连稳定,直至所有染色体完成与纺锤体的连接,"等待-后期"信号失活,SAC启动,使染色体间的黏连失活,进而在纺锤体的作用下染色体分离。作者综述了减数分裂过程中纺锤体的特异性组装过程和纺锤体检查点的组成及作用机制,丰富了减数分裂的相关知识,并为减数分裂过程中非整倍体的形成机制提供依据。
The accurate separation of chromosomes is completed under the correct assembly of spindles and the monitoring of spindle assembly checkpoint(SAC).For the mammalian oocytes,the spindle formation and SAC are the important factors to ensure the accurate separation of chromosomes.If the chromosome is separated incorrectly,it will directly lead to spontaneous abortion or other birth defects.After the oocyte centrosome is deleted,the cells can still form a bipolar spindle by antiparallel arrangement of microtubules which are nucleated around the chromosome independent of the centrosome,that is self-assembled spindle.The microtubules are gathered by the microtubule organization center(MTOC),the maturation promoting factor(MPF)maintains the formation process of the spindle during the two meiosis,and the cytostatic factor(CSF)maintains the metaphase structure,so that the spindle remains stable when the chromosomes do not all converge on the equatorial plate.The heavy volume of sites is prone to aneuploidy,and the particularity that sites don’t contain centrosomes leads to a dispute over whether SAC exists on site for a long time,but now SAC is one of the mechanisms to ensure accurate chromosome separation from sites.There is a kind of adhesion between chromosomes in meiosis metaphors,and the‘wait-later’signal produced by the cell inhibits SAC activity so as to retain the adhesion stable until all chromosomes complete the connection with the spindle,and the‘wait-later’signal is inactivated,SAC starts to inactivate the adhesion between chromosomes,and then chromosomes are separated under the action of the spindle.This paper reviews the specific assembly process of spindles and the composition and mechanism of spindle checkpoints during meiosis,which enriches our understanding of meiosis and provides a basis of the formation mechanism of aneuploid during meiosis.
作者
韩玉萍
曹俊国
杨镒峰
许保增
HAN Yuping;CAO Junguo;YANG Yifeng;XU Baozeng(Institute of Special Animal and Plant of Sciences,Chinese Academy of Agriculture Sciences,Changchun 130112,China)
出处
《中国畜牧兽医》
CAS
北大核心
2019年第4期1094-1100,共7页
China Animal Husbandry & Veterinary Medicine
基金
中国农业科学院基本科研业务费增量项目(2015ZL012)
中国农业科学院科技创新工程(CAAS-ASTIP-2016-ISAPS)
