The histone variant H3.3 marks active chromatin by replication-independent nucleosome assembly
The histone variant H3.3 marks active chromatin by replication-independent nucleosome assembly
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DOI：
10.1016/s1097-2765(02)00542-7
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发表时间：
2002-06-01
期刊：
影响因子：
16
通讯作者：
Henikoff, S
中科院分区：
文献类型：
--
作者：
Ahmad, K;Henikoff, S
果蝇细胞中产生两种非常相似的H3组蛋白，它们仅在四个氨基酸位置上不同。在这里，我们描述了一种染色质调节的机制，即变异H3.3沉积在特定的位点，包括活性rDNA阵列。虽然主要的H3在DNA复制过程中严格掺入，但朝向H3.3的氨基酸变化允许非复制依赖性（RI）沉积。与复制耦合（RC）沉积相反，RI沉积不需要N-末端高。H3.3是RI沉积的唯一底物，其对应物是酵母中保留的唯一底物。H3.3的RI取代提供了一种机制，用于立即激活被组蛋白修饰沉默的基因。然后，新沉积的核小体的遗传可以将位点标记为活性位点。
Two very similar H3 histones-differing at only four amino acid positions-are produced in Drosophila cells. Here we describe a mechanism of chromatin regulation whereby the variant H3.3 is deposited at particular loci, including active rDNA arrays. While the major H3 is incorporated strictly during DNA replication, amino acid changes toward H3.3 allow replication-independent (RI) deposition. In contrast to replication-coupled (RC) deposition, RI deposition does not require the N-terminal tall. H3.3 is the exclusive substrate for RI deposition, and its counterpart is the only substrate retained in yeast. RI substitution of H3.3 provides a mechanism for the immediate activation of genes that are silenced by histone modification. Inheritance of newly deposited nucleosomes may then mark sites as active loci.