Institute of Biophysics, Czechoslovak Academy of Sciences, CS-612 65, Brno, Czechoslovakia.
Planta. 1991 Jul;184(4):487-90. doi: 10.1007/BF00197896.
The methylation status and 5-azacytidine-induced hypomethylation of CCGG sites within a family of tandemly organized, highly repeated DNA sequences of the Nicotiana tabacum L. nuclear genome (HRS60 family) were studied. As shown by in-situ hybridization experiments, the HRS60 family is clustered in a few regions of some tobacco chromosomes. The DNAs of leaf-derived calli, leaf-derived calli cultured on media with 5-azacytidine, and leaves were cleaved with restriction endonucleases differing in the sensitivity to the methylation of cytosine. After electrophoresis and Southern blotting they were hybridized with the HRS60 probe. We show that (i) CpG dinucleotides, and partially also CpCpG trinucleotides, of the HRS60 family are methylated in DNAs of the non-treated calli and leaves, and (ii) that these DNA repeats are sensitive to the action of a hypomethylating drug, 5-azacytidine.
我们研究了烟草 L. 核基因组（HRS60 家族）中串联排列的高度重复 DNA 序列内 CCGG 位点的甲基化状态和 5-氮杂胞苷诱导的去甲基化。原位杂交实验表明，HRS60 家族在一些烟草染色体的少数区域聚集。来自叶片衍生的愈伤组织、在含有 5-氮杂胞苷的培养基上培养的叶片衍生的愈伤组织以及叶片的 DNA 用对胞嘧啶甲基化敏感性不同的限制内切酶进行切割。电泳和 Southern 印迹后，它们与 HRS60 探针杂交。我们表明：（i）未处理的愈伤组织和叶片 DNA 中 HRS60 家族的 CpG 二核苷酸，部分 CpCpG 三核苷酸，是甲基化的，（ii）这些 DNA 重复序列对去甲基化药物 5-氮杂胞苷敏感。
