Wellcome Trust Centre for Cell Biology and Institute of Cell Biology, The University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom.
J Biol Chem. 2011 Jul 1;286(26):23600-7. doi: 10.1074/jbc.M111.228510. Epub 2011 Apr 28.
The histone H3 variant CENP-A is the most favored candidate for an epigenetic mark that specifies the centromere. In fission yeast, adjacent heterochromatin can direct CENP-A(Cnp1) chromatin establishment, but the underlying features governing where CENP-A(Cnp1) chromatin assembles are unknown. We show that, in addition to centromeric regions, a low level of CENP-A(Cnp1) associates with gene promoters where histone H3 is depleted by the activity of the Hrp1(Chd1) chromatin-remodeling factor. Moreover, we demonstrate that noncoding RNAs are transcribed by RNA polymerase II (RNAPII) from CENP-A(Cnp1) chromatin at centromeres. These analyses reveal a similarity between centromeres and a subset of RNAPII genes and suggest a role for remodeling at RNAPII promoters within centromeres that influences the replacement of histone H3 with CENP-A(Cnp1).
组蛋白 H3 变体 CENP-A 是指定着丝粒的表观遗传标记的最受欢迎的候选物。在裂殖酵母中,相邻的异染色质可以指导 CENP-A(Cnp1)染色质的建立,但控制 CENP-A(Cnp1)染色质组装位置的基本特征尚不清楚。我们表明,除了着丝粒区域外,低水平的 CENP-A(Cnp1)与基因启动子相关联,在这些启动子中,Hrp1(Chd1)染色质重塑因子的活性导致组蛋白 H3 耗竭。此外,我们证明非编码 RNA 由 RNA 聚合酶 II(RNAPII)从着丝粒处的 CENP-A(Cnp1)染色质转录。这些分析揭示了着丝粒和 RNA 聚合酶 II 基因的一个亚类之间的相似性,并表明在影响用 CENP-A(Cnp1)替代组蛋白 H3 的过程中,着丝粒内的重塑作用在 RNAPII 启动子中起作用。