Hendzel M J, Sun J M, Chen H Y, Rattner J B, Davie J R
Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
J Biol Chem. 1994 Sep 9;269(36):22894-901.
Only a small fraction of the adult chicken erythrocyte histones is involved in dynamic acetylation. We have reported previously that the rapidly acetylated and deacetylated H4 histones are primarily associated with the transcriptionally active DNA-enriched chromatin fragments that remain attached to the residual nuclear material following micrococcal nuclease digestion and chromatin solubilization. Furthermore, this nuclear fraction contained most of the histone deacetylase activity. In this study we show that the bulk of the nuclear histone acetyltransferase activity is located with the insoluble residual nuclear material. We demonstrate that in vitro the enzymes associated with the residual nuclear material catalyze reversible acetylation when the endogenous histones of the nuclear skeleton-bound chromatin fragments are used as substrate. Nuclear matrices isolated from adult chicken immature erythrocyte and trout liver nuclei had 60-76% of the nuclear histone acetyltransferase activity. Procedures that solubilized the internal nuclear matrix also resulted in the release of the enzyme from the nuclear matrix. Together, our observations suggest that histone acetyltransferase and deacetylase are associated with the internal nuclear matrix, and one of the functions of these enzymes may be to mediate a dynamic attachment between transcriptionally active chromatin and the nuclear matrix.
成年鸡红细胞组蛋白中只有一小部分参与动态乙酰化。我们之前报道过，快速乙酰化和去乙酰化的H4组蛋白主要与转录活性的富含DNA的染色质片段相关，这些片段在微球菌核酸酶消化和染色质溶解后仍附着于残留核物质上。此外，该核部分含有大部分组蛋白脱乙酰酶活性。在本研究中，我们表明大部分核组蛋白乙酰转移酶活性位于不溶性残留核物质中。我们证明，当以核骨架结合的染色质片段的内源性组蛋白为底物时，与残留核物质相关的酶在体外催化可逆乙酰化。从成年鸡未成熟红细胞和鳟鱼肝细胞核中分离出的核基质具有60 - 76%的核组蛋白乙酰转移酶活性。使内核基质溶解的操作也导致该酶从核基质中释放出来。我们的观察结果共同表明，组蛋白乙酰转移酶和脱乙酰酶与内核基质相关，这些酶的功能之一可能是介导转录活性染色质与核基质之间的动态连接。
