Department of Molecular Genetics, National Institute of Genetics and The Graduate University for Advanced Studies (SOKENDAI), Mishima, Shizuoka 411-8540, Japan.
Comparative Genomics Laboratory, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
Dev Cell. 2014 Jun 23;29(6):740-9. doi: 10.1016/j.devcel.2014.05.001.
In vertebrate cells, centromeres are specified epigenetically through the deposition of the centromere-specific histone CENP-A. Following CENP-A deposition, additional proteins are assembled on centromeric chromatin. However, it remains unknown whether additional epigenetic features of centromeric chromatin are required for kinetochore assembly. Here, we used ChIP-seq analysis to examine centromere-specific histone modifications at chicken centromeres, which lack highly repetitive sequences. We found that H4K20 monomethylation (H4K20me1) is enriched at centromeres. Immunofluorescence and biochemical analyses revealed that H4K20me1 is present at all centromeres in chicken and human cells. Based on immunoprecipitation data, H4K20me1 occurs primarily on the histone H4 that is assembled as part of the CENP-A nucleosome following deposition of CENP-A into centromeres. Targeting the H4K20me1-specific demethylase PHF8 to centromeres reduces the level of H4K20me1 at centromeres and results in kinetochore assembly defects. We conclude that H4K20me1 modification of CENP-A nucleosomes contributes to functional kinetochore assembly.
在脊椎动物细胞中，通过沉积特异性组蛋白 CENP-A 来实现着丝粒的表观遗传特异性指定。在 CENP-A 沉积后，会在着丝粒染色质上组装其他蛋白质。然而，是否需要着丝粒染色质的其他表观遗传特征来进行动粒组装仍然未知。在这里，我们使用 ChIP-seq 分析来检查鸡着丝粒的特异性组蛋白修饰，鸡着丝粒缺乏高度重复的序列。我们发现 H4K20 单甲基化（H4K20me1）在着丝粒处富集。免疫荧光和生化分析显示，H4K20me1 存在于鸡和人细胞的所有着丝粒上。基于免疫沉淀数据，H4K20me1 主要发生在组装为 CENP-A 核小体一部分的组蛋白 H4 上，CENP-A 沉积到着丝粒后，H4K20me1 就会发生。将 H4K20me1 特异性去甲基酶 PHF8 靶向到着丝粒会降低着丝粒处 H4K20me1 的水平，并导致动粒组装缺陷。我们的结论是，CENP-A 核小体的 H4K20me1 修饰有助于功能性动粒组装。
