Partridge J F, Borgstrøm B, Allshire R C
Medical Research Council (MRC) Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, Scotland, UK.
Genes Dev. 2000 Apr 1;14(7):783-91.
Fission yeast (Schizosaccharomyces pombe) centromeres are composed of large (40-100 kb) inverted repeats that display heterochromatic features, thus providing a good model for higher eukaryotic centromeres. The association of three proteins that mediate region-specific silencing across centromere 1 has been mapped by quantitative chromatin immunoprecipitation. Swi6 and Chp1 are confined to the flanking outer repeats and Swi6 can spread across at least 3 kb of extraneous chromatin in cen1. In contrast, Mis6 coats the inner repeats and central core. tRNA genes demarcate this transition zone. These analyses clearly define two distinct domains within this complex centromere which interact with different proteins.
裂殖酵母（粟酒裂殖酵母）的着丝粒由大型（40 - 100 kb）反向重复序列组成，这些序列呈现异染色质特征，因此为高等真核生物着丝粒提供了一个良好的模型。通过定量染色质免疫沉淀法已绘制出三种介导跨越着丝粒1区域特异性沉默的蛋白质的关联图谱。Swi6和Chp1局限于侧翼外侧重复序列，并且Swi6可以在cen1中跨越至少3 kb的外来染色质扩散。相比之下，Mis6覆盖内部重复序列和中央核心。tRNA基因划定了这个过渡区。这些分析清楚地定义了这个复杂着丝粒内两个不同的结构域，它们与不同的蛋白质相互作用。
