S-腺苷酰L-甲硫氨酸 (SAM)对 HL-60细胞 DNA甲基化酶活力和甲基化水平的影响(英文)

 以 S-腺苷酰 - L-甲硫氨酸 (SAM)为诱导物 ,在 1 0 μmol/L最佳浓度下造成 1 6%的 HL- 60细胞分化 .HPLC检测结果表明 ,细胞基因组 DNA甲基化水平升高 .通过3H甲基同位素参入法研究细胞 DNA甲基化酶活力 ,则发现在细胞分化过程中酶活力未见升高 .说明细胞基因组甲基化水平升高并不是胞内 DNA甲基化酶催化能力改变的结果 ,而是由于 SAM进入细胞提供过量甲基造成的 .

The Effect of S-adenosy1-L-methionine (SAM) on DNA Methylase Activities and DNA Methylation Level in HL-60 Cells

The differentiation index of HL 60 cells was measured after HL 60 cells were treated with S adenosyl L methionine (SAM) by using the NBT staining method.The value of differentiation index was 16% or so when the concentration of SAM was 10 μmol/L.The methylation level of genomic DNA of HL 60 was analysed by HPLC.It was found that the DNA methylation level of SAM treated cells increased compared with control cells.The DNA methylase activities of HL 60 cells treated with SAM were assayed by using 3H methyl SAM as methyl donor,but it did not show that HL 60 cells treated with SAM had higher activities than control cells.All these demonstrated that the increase of DNA methylation level was the result of more methyl group in the cells provided by SAM,rather than the change of DNA methylase activities.