Demethylation of somatic and testis-specific histone H2A and H2B genes in F9 embryonal carcinoma cells.
Demethylation of somatic and testis-specific histone H2A and H2B genes in F9 embryonal carcinoma cells.
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F9 胚胎癌细胞中体细胞和睾丸特异性组蛋白 H2A 和 H2B 基因的去甲基化。
DOI：
10.1128/mcb.13.9.5538-5548.1993
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发表时间：
1993
影响因子：
5.3
通讯作者：
Chae,CB
中科院分区：
文献类型：
--
作者：
Choi,YC;Chae,CB
与许多其他含有CpG岛的基因相反，睾丸特异性H2 B（TH 2B）组蛋白基因表现出与基因活性相关的组织特异性甲基化模式。与体细胞组蛋白簇中的甲基化模式相比，含有TH 2A和TH 2B基因的20-kb片段内的甲基化模式的表征揭示：（i）TH 2A和TH 2B基因的生殖细胞特异性未甲基化结构域被定义为围绕TH 2A和TH 2B基因的CpG岛的小区域，和（ii）体细胞组蛋白基因在肝和生殖细胞中都未甲基化，像其他含有CpG岛的基因一样，而侧翼序列是甲基化的。体外甲基化的TH 2B，体细胞H2 B，和小鼠金属硫蛋白I结构转染到F9胚胎癌细胞中，发现TH 2A和TH 2B基因的CpG岛被去甲基化，就像那些体细胞H2 A和H2 B基因和金属硫蛋白I基因。这些CpG岛的去甲基化在高数目的整合拷贝和高密度的甲基化CpG二核苷酸时变得显著低效。相反，在体细胞组蛋白簇中的三个位点，其中两个位点位于内源性逆转录病毒样序列的长末端重复序列中，即使在高拷贝数和高密度的甲基化CpG二核苷酸下也有效地去甲基化。这些结果表明两种可能的机制F9细胞中的去甲基化和甲基化的CpG岛的TH 2A和TH 2B基因在囊胚后阶段在胚胎发生。
In contrast to many other genes containing a CpG island, the testis-specific H2B (TH2B) histone gene exhibits tissue-specific methylation patterns in correlation with gene activity. Characterization of the methylation patterns within a 20-kb segment containing the TH2A and TH2B genes in comparison with that in a somatic histone cluster revealed that: (i) the germ cell-specific unmethylated domain of the TH2A and TH2B genes is defined as a small region surrounding the CpG islands of the TH2A and TH2B genes and (ii) somatic histone genes are unmethylated in both liver and germ cells, like other genes containing CpG islands, whereas flanking sequences are methylated. Transfection of in vitro-methylated TH2B, somatic H2B, and mouse metallothionein I constructs into F9 embryonal carcinoma cells revealed that the CpG islands of the TH2A and TH2B genes were demethylated like those of the somatic H2A and H2B genes and the metallothionein I gene. The demethylation of those CpG islands became significantly inefficient at a high number of integrated copies and a high density of methylated CpG dinucleotides. In contrast, three sites in the somatic histone cluster, of which two sites are located in the long terminal repeat of an endogenous retrovirus-like sequence, were efficiently demethylated even at a high copy number and a high density of methylated CpG dinucleotides. These results suggest two possible mechanisms for demethylation in F9 cells and methylation of CpG islands of the TH2A and TH2B genes at the postblastula stage during embryogenesis.