Transcription and Disease Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India.
Biochemistry. 2010 Feb 23;49(7):1355-7. doi: 10.1021/bi9021632.
The chromatin is comprised of repeating subunits that make up the nucleosome which is composed of an octamer of histones: H3, H4, H2A, and H2B. The replication-dependent and -independent nucleosome assembly occurs in an ordered fashion and is aided by cellular proteins such as histone chaperones and chromatin remodelers. Previously, we found that the histone chaperone NPM1 activates transcription from the chromatin template. Here we report that NPM3, a member of the nucleophosmin/nucleoplasmin family, lacks intrinsic histone chaperone activity, inhibits histone assembly activity of NPM1 in vitro, and dramatically enhances transcription in a cellular system.
染色质由重复的亚基组成，这些亚基构成核小体，核小体由组蛋白 H3、H4、H2A 和 H2B 的八聚体组成。依赖于复制和不依赖于复制的核小体组装以有序的方式发生，并得到细胞蛋白（如组蛋白伴侣和染色质重塑因子）的辅助。之前，我们发现组蛋白伴侣 NPM1 激活来自染色质模板的转录。在这里，我们报告说，核磷蛋白/核质素家族的成员 NPM3 缺乏内在的组蛋白伴侣活性，体外抑制 NPM1 的组蛋白组装活性，并在细胞系统中显著增强转录。
