DISTRIBUTION AND TURNOVER OF LABELED METHYL GROUPS IN HISTONE FRACTIONS OF CULTURED MAMMALIAN-CELLS
DISTRIBUTION AND TURNOVER OF LABELED METHYL GROUPS IN HISTONE FRACTIONS OF CULTURED MAMMALIAN-CELLS
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DOI：
10.1016/0003-9861(72)90174-9
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发表时间：
1972-01-01
影响因子：
3.9
通讯作者：
HARDIN, JM
中科院分区：
文献类型：
--
作者：
BYVOET, P;SHEPHERD, GR;HARDIN, JM
随机培养的哺乳动物细胞用[14C-Me]-蛋氨酸标记。细胞在标记后直接收获，或在未标记的培养液中进一步生长不同时期后收获。收获的细胞被分成胞浆、核浆、组蛋白和残留蛋白质组分。用水解法和离子交换层析法测定了各组分的放射性甲基活度分布，用水解法和气相色谱测定了挥发性放射性甲基组分的分布。甲基化赖氨酸残基的比活性在组蛋白中显著高于任何其他组分，而核质和残存蛋白中含有比活性高于组蛋白的甲基精氨酸。在组蛋白组分中，只有F2b含有甲基化精氨酸。在这些组分中，只有组蛋白经过短暂的碱解后，发现其主要挥发性成分为甲醇。组蛋白组分及其甲基赖氨酸和甲基精氨酸组分的半衰期比较表明，组蛋白甲基化是不可逆的。
Random cultures of mammalian cells were labeled with [14C-Me]-methionine. Cells were harvested either directly after labeling or after varying periods of further growth in unlabeled medium. Harvested cells were fractionated into cytosol, nucleoplasm, histone, and residual protein fractions. The distribution of radiomethyl activity among the amino acids of each fraction was determined by hydrolysis and ion-exchange chromatography, while the distribution of volatile radiomethyl components was determined by hydrolysis and gas chromatography. The specific activities of methylated lysine residues were found to be considerably higher in histones than in any other fraction, while the nucleoplasm and residual proteins contained methyl arginine at higher specific activities than did the histones. Among the histone fractions, only F2b was found to contain methylated arginine. Among the fractions, only histones were found to contain methanol as their main volatile component after brief alkaline hydrolysis. A comparison of the half-lives of histone fractions and their methyl lysine and methyl arginine components indicated that histone methylation was irreversible.