Allshire R C
MRC Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK.
Curr Opin Genet Dev. 1997 Apr;7(2):264-73. doi: 10.1016/s0959-437x(97)80137-2.
An emerging view is that the formation of active centromeres is modulated in an epigenetic manner reflecting the association of centromeres with heterochromatin. Support for this comes from studies on fission yeast centromeres, the properties of human neocentromeres and dicentric chromosomes, and analyses of Drosophila minichromosome deletion derivatives. A link has been established between tension across kinetochores and the phosphorylation status of kinetochore components. Vertebrate homologues of yeast MAD2 have recently been isolated and localized to kinetochores, indicating that components of the spindle integrity checkpoint are conserved. The linkage between sister chromatids is only dissolved at anaphase during mitotic and meiotic divisions. Phenotypic and localization data combined with their pattern of rapid degradation at anaphase have implicated several yeast and Drosophila proteins in aspects of sister chromatid cohesion.
一种新出现的观点认为，活性着丝粒的形成是以一种表观遗传方式调控的，这反映了着丝粒与异染色质的关联。对此的支持来自对裂殖酵母着丝粒的研究、人类新着丝粒和双着丝粒染色体的特性，以及对果蝇微小染色体缺失衍生物的分析。已经在动粒上的张力与动粒组分的磷酸化状态之间建立了联系。酵母MAD2的脊椎动物同源物最近已被分离并定位于动粒，这表明纺锤体完整性检查点的组分是保守的。姐妹染色单体之间的连接仅在有丝分裂和减数分裂的后期溶解。表型和定位数据，以及它们在后期快速降解的模式，表明几种酵母和果蝇蛋白质参与了姐妹染色单体黏连的各个方面。
