Deng Wenwen, Yang Mo, Zhang Zunzhen, Wu Mei
Department of Environmental Health, West China School of Public Health, Sichuan University, Chengdu 610041, China.
Wei Sheng Yan Jiu. 2013 Nov;42(6):915-9, 924.
To investigate the expression level and enzymatic activity of DNA methylation transferases (dnmts) in mouse embryonic fibroblast malignant transformed cells induced by benzopyrene (B[a]P).
Two kinds of cell lines, pol beta wild-type cells (pol beta +/+) and malignant transformation cells induced by BaP (pol beta-T) were applied as cellular models. Pol beta +/+ cells were served as controls, RT-PCR and Western blot were used to measure the change of dnmts expression level in malignant transformation cells induced by BaP. The enzymatic activity of DNMTs was also detected with DNA methyltransferase (DNMT) activity/inhibition assay kit.
The mRNA and protein expression levels of dnmt1 and dnmt3b in pol beta-T cells (0.940 +/- 0.033 and 0.905 +/- 0.062) were much higher than that in pol beta +/+ cells (0.560 +/- 0.031 and 0.666 +/- 0.041), however the expression level of dnmt3a had no difference between these two cell lines. On the contrary, the enzymatic activity level of DNMTs in pol beta-T cells ((329.48 +/- 52.11) OD x h(-1) x mg(-1)) was much lower than that in pol beta +/+ cells ((253.70 +/- 20.56) OD x h(-1) x mg(-1)).
The over expression of dnmt1 and dnmt3b and the change of DNMTs activity may be contribute to the cell malignant transformation process induced by BaP.
研究苯并芘（B[a]P）诱导的小鼠胚胎成纤维细胞恶性转化细胞中DNA甲基转移酶（dnmts）的表达水平和酶活性。
以两种细胞系，即polβ野生型细胞（polβ+/+）和BaP诱导的恶性转化细胞（polβ-T）作为细胞模型。将polβ+/+细胞作为对照，采用RT-PCR和蛋白质免疫印迹法检测BaP诱导的恶性转化细胞中dnmts表达水平的变化。还用DNA甲基转移酶（DNMT）活性/抑制检测试剂盒检测DNMTs的酶活性。
polβ-T细胞中dnmt1和dnmt3b的mRNA和蛋白表达水平（分别为0.940±0.033和0.905±0.062）显著高于polβ+/+细胞（分别为0.560±0.031和0.666±0.041），然而这两种细胞系中dnmt3a的表达水平没有差异。相反，polβ-T细胞中DNMTs的酶活性水平（（329.48±52.11）OD×h-1×mg-1）显著低于polβ+/+细胞（（253.70±20.56）OD×h-1×mg-1）。
dnmt1和dnmt3b的过表达以及DNMTs活性的变化可能促成了BaP诱导的细胞恶性转化过程。
