He Z X, Rao H
Department of Biology, Beijing Normal University, PRC.
Sci China B. 1993 Apr;36(4):430-8.
The effect of 5-aza-CR and 5-aza-2'-deoxycytidine (5-aza-CdR) on cell differentiation and DNA methylation of HL-60 cells was studied. The differentiation index of HL-60 cells was measured after being treated with drugs by using the NBT stain method. DNA methylase activities of HL-60 cells treated with the drugs were assayed by using 3H-methyl-S-adenosylmethionine (3H-SAM) as a methyl donor. The DNA methylation level of HL-60 cells treated with the drugs was measured by HPLC. The results showed that the HL-60 cell differentiation index was increased after being treated with 5-aza-CR or 5-aza-CdR at a certain concentration for 4 days. But, at the same time, DNA methylase activity and the DNA methylation level were decreased. And all these changes were related to the concentration of the drugs. 5-Aza-CdR was more efficient than 5-aza-CR. We also assayed the E. coli RNA polymerase activity in vitro by using different DNA templets different in DNA methylation level. We found that the transcriptional activity of RNA polymerase was increased with the decrease of the DNA methylation level of HL-60 cells.
研究了5-氮杂胞苷（5-aza-CR）和5-氮杂-2'-脱氧胞苷（5-aza-CdR）对HL-60细胞分化及DNA甲基化的影响。采用NBT染色法检测药物处理后HL-60细胞的分化指数。以3H-甲基-S-腺苷甲硫氨酸（3H-SAM）作为甲基供体，检测药物处理后HL-60细胞的DNA甲基化酶活性。用高效液相色谱法测定药物处理后HL-60细胞的DNA甲基化水平。结果显示，一定浓度的5-aza-CR或5-aza-CdR处理4天后，HL-60细胞分化指数升高。但与此同时，DNA甲基化酶活性及DNA甲基化水平降低。所有这些变化均与药物浓度有关。5-aza-CdR比5-aza-CR更有效。我们还使用不同DNA甲基化水平的DNA模板体外检测了大肠杆菌RNA聚合酶活性。我们发现，随着HL-60细胞DNA甲基化水平的降低，RNA聚合酶的转录活性增强。
