多胺和阳离子对组蛋白体外甲基化的影响。

Effect of polyamines and cations on the in vitro methylation of histones.

作者信息

Duerre J A, Quick D P, Traynor M D, Onisk D V

出版信息

Biochim Biophys Acta. 1982 Oct 28;719(1):18-23. doi: 10.1016/0304-4165(82)90301-4.

Abstract

Na+ (0.05-0.15 M) increases both the rate and extent of methylation of chromosomal bound histone H4, while spermidine markedly inhibits this reaction. The effects of spermidine could be mimicked by increasing the concentration of Mg2+ or Ca2+ to 5-10 mM. At the concentrations listed above, these cations have no significant effect on the methylation of free or chromosomal bound histone H3, nor do they affect the rate r extent of methylation of soluble histone H4. Apparently, the accessibility of histone H4 to the methyltransferase is influenced by chromatin structure. Increasing concentrations of Na+ alter the conformation of chromatin (DNA) in such a way as to expose lysing residues in the N-terminal region of histone H4 to the methyltransferase, whereas Mg2+ or spermidine acts in an opposite manner.

摘要

0.05 - 0.15M的Na⁺可提高染色体结合组蛋白H4的甲基化速率和程度，而亚精胺则显著抑制该反应。将Mg²⁺或Ca²⁺浓度提高到5 - 10mM可模拟亚精胺的作用。在上述浓度下，这些阳离子对游离或染色体结合组蛋白H3的甲基化无显著影响，也不影响可溶性组蛋白H4的甲基化速率或程度。显然，组蛋白H4对甲基转移酶的可及性受染色质结构影响。Na⁺浓度增加会改变染色质（DNA）的构象，使组蛋白H4 N端区域的赖氨酸残基暴露于甲基转移酶，而Mg²⁺或亚精胺的作用则相反。