Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut, USA.
PLoS Genet. 2013;9(1):e1003209. doi: 10.1371/journal.pgen.1003209. Epub 2013 Jan 17.
Accurate chromosome segregation requires centromeres (CENs), the DNA sequences where kinetochores form, to attach chromosomes to microtubules. In contrast to most eukaryotes, which have broad centromeres, Saccharomyces cerevisiae possesses sequence-defined point CENs. Chromatin immunoprecipitation followed by sequencing (ChIP-Seq) reveals colocalization of four kinetochore proteins at novel, discrete, non-centromeric regions, especially when levels of the centromeric histone H3 variant, Cse4 (a.k.a. CENP-A or CenH3), are elevated. These regions of overlapping protein binding enhance the segregation of plasmids and chromosomes and have thus been termed Centromere-Like Regions (CLRs). CLRs form in close proximity to S. cerevisiae CENs and share characteristics typical of both point and regional CENs. CLR sequences are conserved among related budding yeasts. Many genomic features characteristic of CLRs are also associated with these conserved homologous sequences from closely related budding yeasts. These studies provide general and important insights into the origin and evolution of centromeres.
准确的染色体分离需要着丝粒（CENs），即动粒形成的 DNA 序列，将染色体与微管连接。与大多数真核生物具有广泛的着丝粒不同，酿酒酵母具有序列定义的点状着丝粒。染色质免疫沉淀测序（ChIP-Seq）揭示了四个着丝粒蛋白在新的、离散的、非着丝粒区域的共定位，尤其是当着丝粒组蛋白 H3 变体 Cse4（又名 CENP-A 或 CenH3）的水平升高时。这些蛋白质结合的重叠区域增强了质粒和染色体的分离，因此被称为着丝粒样区域（CLRs）。CLRs 与酿酒酵母的 CEN 紧密接近，并具有点状和区域性 CEN 的典型特征。CLR 序列在相关的芽殖酵母中是保守的。许多与 CLRs 相关的基因组特征也与这些来自密切相关的芽殖酵母的保守同源序列相关。这些研究为着丝粒的起源和进化提供了普遍而重要的见解。
