Structures of human nucleosomes containing major histone H3 variants
Structures of human nucleosomes containing major histone H3 variants
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DOI：
10.1107/s0907444911014818
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发表时间：
2011-06-01
期刊：
影响因子：
--
通讯作者：
Kurumizaka, Hitoshi
中科院分区：
文献类型：
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作者：
Tachiwana, Hiroaki;Osakabe, Akihisa;Kurumizaka, Hitoshi
核小体是染色质的基本重复单位，基因组 DNA 通过它被包装到真核生物的细胞核中。在核小体中，每个核心组蛋白的两个拷贝（H2A、H2B、H3 和 H4）形成组蛋白八聚体，将 146 个 DNA 碱基对包裹在其自身周围。除组蛋白 H4 外，所有核心组蛋白均具有称为组蛋白变体的非等位基因亚型。在人类中，迄今为止已报道了八种组蛋白 H3 变体：H3.1、H3.2、H3.3、H3T、H3.5、H3.X、H3.Y 和 CENP-A。先前的研究表明，组蛋白 H3 变体在特定染色体区域的形成和/或转录和复制的调节中具有独特的功能。 H3.1、H3.2 和 H3.3 是最丰富的 H3 变体。在此，含有 H3.2 或 H3.3 的人类核小体的晶体结构已得到解决。其结构与H3.1核小体的结构基本相同。由于 H3.2 和 H3.3 特异性的氨基酸残基位于 H3/H4 四聚体的可及表面上，因此它们可能是 H3.2 和 H3.3 特异性伴侣的潜在相互作用位点。
The nucleosome is the fundamental repeating unit of chromatin, via which genomic DNA is packaged into the nucleus in eukaryotes. In the nucleosome, two copies of each core histone, H2A, H2B, H3 and H4, form a histone octamer which wraps 146 base pairs of DNA around itself. All of the core histones except for histone H4 have nonallelic isoforms called histone variants. In humans, eight histone H3 variants, H3.1, H3.2, H3.3, H3T, H3.5, H3.X, H3.Y and CENP-A, have been reported to date. Previous studies have suggested that histone H3 variants possess distinct functions in the formation of specific chromosome regions and/or in the regulation of transcription and replication. H3.1, H3.2 and H3.3 are the most abundant H3 variants. Here, crystal structures of human nucleosomes containing either H3.2 or H3.3 have been solved. The structures were essentially the same as that of the H3.1 nucleosome. Since the amino-acid residues specific for H3.2 and H3.3 are located on the accessible surface of the H3/H4 tetramer, they may be potential interaction sites for H3.2- and H3.3-specific chaperones.