Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA.
Exp Cell Res. 2012 Jul 15;318(12):1353-60. doi: 10.1016/j.yexcr.2012.04.007. Epub 2012 Apr 27.
The centromere is the fundamental unit for insuring chromosome inheritance. This complex region has a distinct type of chromatin in which histone H3 is replaced by a structurally different homologue identified in humans as CENP-A. In metazoans, specific DNA sequences are neither required nor sufficient for centromere identity. Rather, an epigenetic mark comprised of CENP-A containing chromatin is thought to be the major determinant of centromere identity. In this view, CENP-A deposition and chromatin assembly are fundamental processes for the maintenance of centromeric identity across mitotic and meiotic divisions. Several lines of evidence support CENP-A deposition in metazoans occurring at only one time in the cell cycle. Such cell cycle-dependent loading of CENP-A is found in divergent species from human to fission yeast, albeit with differences in the cell cycle point at which CENP-A is assembled. Cell cycle dependent CENP-A deposition requires multiple assembly factors for its deposition and maintenance. This review discusses the regulation of new CENP-A deposition and its relevance to centromere identity and inheritance.
着丝粒是确保染色体遗传的基本单位。这个复杂的区域具有一种独特类型的染色质,其中组蛋白 H3 被在人类中鉴定为 CENP-A 的结构不同的同源物所取代。在后生动物中,特定的 DNA 序列既不是着丝粒身份所必需的,也不是充分的。相反,由包含 CENP-A 的染色质组成的表观遗传标记被认为是着丝粒身份的主要决定因素。在这种观点中,CENP-A 的沉积和染色质组装是维持有丝分裂和减数分裂过程中着丝粒身份的基本过程。有几条证据支持在细胞周期中只有一次在后生动物中发生 CENP-A 沉积。尽管在组装 CENP-A 的细胞周期点上存在差异,但在从人类到裂殖酵母的不同物种中都发现了这种细胞周期依赖性的 CENP-A 加载。细胞周期依赖性 CENP-A 沉积需要多个组装因子来进行沉积和维持。这篇综述讨论了新的 CENP-A 沉积的调节及其与着丝粒身份和遗传的相关性。