Folger K, Anderson J N, Hayward M A, Shapiro D J
J Biol Chem. 1983 Jul 25;258(14):8908-14.
Estrogen activates transcription of the vitellogenin genes in livers of male Xenopus laevis. We have examined the conformation of the vitellogenin genes in chromatin and the methylation state of one vitellogenin gene during the process of estrogen stimulation and withdrawal. Sensitivity of the vitellogenin genes to DNase I digestion parallels transcription. The vitellogenin genes are insensitive to DNase I digestion in unstimulated liver cells, become more sensitive to DNase I digestion following estrogen activation of vitellogenin gene transcription, and are insensitive to DNase I digestion in liver cells withdrawn from estrogen. In contrast, the methylation state of nine potential methylation sites within the vitellogenin A1 gene is identical in red blood cells, unstimulated and withdrawn liver, estrogen-stimulated liver, and hepatocytes purified from estrogen-stimulated liver. Rapid transcription of the vitellogenin genes in estrogen-stimulated liver cells occurs with six of the nine methylation sites examined fully methylated.
雌激素可激活雄性非洲爪蟾肝脏中卵黄蛋白原基因的转录。我们研究了在雌激素刺激和撤除过程中，染色质中卵黄蛋白原基因的构象以及一个卵黄蛋白原基因的甲基化状态。卵黄蛋白原基因对脱氧核糖核酸酶I消化的敏感性与转录情况相似。在未受刺激的肝细胞中，卵黄蛋白原基因对脱氧核糖核酸酶I消化不敏感；在雌激素激活卵黄蛋白原基因转录后，对脱氧核糖核酸酶I消化变得更加敏感；而在撤除雌激素的肝细胞中，对脱氧核糖核酸酶I消化又不敏感。相比之下，卵黄蛋白原A1基因内九个潜在甲基化位点的甲基化状态在红细胞、未受刺激和已撤除雌激素的肝脏、雌激素刺激的肝脏以及从雌激素刺激的肝脏中纯化得到的肝细胞中是相同的。在雌激素刺激的肝细胞中，卵黄蛋白原基因的快速转录发生在九个被检测的甲基化位点中的六个完全甲基化的情况下。
