Gerber-Huber S, May F E, Westley B R, Felber B K, Hosbach H A, Andres A C, Ryffel G U
Cell. 1983 May;33(1):43-51. doi: 10.1016/0092-8674(83)90333-1.
The methylation-sensitive restriction enzymes Hha I and Hpa II were used to analyze the methylation pattern of four Xenopus laevis genes in DNA of embryos, of erythrocytes, and of untreated and estrogen-treated hepatocytes. Within these four genes all sites tested are fully modified in embryonic DNA. However, the adult beta 1-globin gene is unmethylated in DNA of erythrocytes, where it is expressed, and the 68 kd albumin gene, active only in hepatocytes, is specifically hypomethylated in hepatic DNA. The vitellogenin genes A1 and A2, in hepatocytes simultaneously expressed upon estrogen treatment, are heavily methylated in all adult tissues, irrespective of expression. Our results reveal that specific genes can be actively transcribed even when they are fully methylated and that changes in the methylation pattern are not a general prerequisite for gene activation.
使用甲基化敏感限制酶Hha I和Hpa II来分析非洲爪蟾四个基因在胚胎DNA、红细胞DNA以及未处理和雌激素处理的肝细胞DNA中的甲基化模式。在这四个基因中，所有测试位点在胚胎DNA中均被完全修饰。然而，成年β1-珠蛋白基因在其表达的红细胞DNA中未甲基化，而仅在肝细胞中活跃的68 kd白蛋白基因在肝脏DNA中特异性低甲基化。雌激素处理后在肝细胞中同时表达的卵黄蛋白原基因A1和A2，在所有成年组织中均高度甲基化，与表达情况无关。我们的结果表明，特定基因即使在完全甲基化时也能被积极转录，并且甲基化模式的变化并非基因激活的普遍先决条件。
