Tadeu Ana Mafalda Baptista, Ribeiro Susana, Johnston Josiah, Goldberg Ilya, Gerloff Dietlind, Earnshaw William C
Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
EMBO J. 2008 Oct 8;27(19):2510-22. doi: 10.1038/emboj.2008.175. Epub 2008 Sep 4.
The mechanism of mitotic chromosome condensation is poorly understood, but even less is known about the mechanism of formation of the primary constriction, or centromere. A proteomic analysis of mitotic chromosome scaffolds led to the identification of CENP-V, a novel kinetochore protein related to a bacterial enzyme that detoxifies formaldehyde, a by-product of histone demethylation in eukaryotic cells. Overexpression of CENP-V leads to hypercondensation of pericentromeric heterochromatin, a phenotype that is abolished by mutations in the putative catalytic site. CENP-V depletion in HeLa cells leads to abnormal expansion of the primary constriction of mitotic chromosomes, mislocalization and destabilization of the chromosomal passenger complex (CPC) and alterations in the distribution of H3K9me3 in interphase nucleoplasm. CENP-V-depleted cells suffer defects in chromosome alignment in metaphase, lagging chromosomes in anaphase, failure of cytokinesis and rapid cell death. CENP-V provides a novel link between centromeric chromatin, the primary constriction and the CPC.
有丝分裂染色体凝聚的机制目前了解甚少,而对于初级缢痕即着丝粒的形成机制所知更少。一项对有丝分裂染色体支架的蛋白质组学分析导致了CENP-V的鉴定,CENP-V是一种新型的动粒蛋白,与一种可解除真核细胞中组蛋白去甲基化副产物甲醛毒性的细菌酶相关。CENP-V的过表达导致着丝粒周围异染色质的过度凝聚,该表型可被假定催化位点的突变消除。HeLa细胞中CENP-V的缺失导致有丝分裂染色体初级缢痕异常扩张、染色体乘客复合体(CPC)定位错误和不稳定以及间期核质中H3K9me3分布改变。CENP-V缺失的细胞在中期存在染色体排列缺陷、后期出现落后染色体、胞质分裂失败并迅速死亡。CENP-V在着丝粒染色质、初级缢痕和CPC之间提供了一种新的联系。