Fig. 1.

Expression of Dnmt1, Dnmt3a, Dnmt3b and Dnmt3l in SHS exposed mice versus control. Total RNA was extracted from the lungs of mice exposed to SHS for four months, immediately after discontinuation of exposure (T⁴) and following 7-month recovery in clean air (T⁴⁺⁷). The transcription level of genes encoding major DNMTs was examined by qRT-PCR using the 2^−ΔΔCt method [41]. Bars represent the mean normalized expression (±SD) of triplicate samples in SHS-exposed mice and age-matched controls. Data were normalized using the endogenous housekeeping gene, Gapdh, as reference and controls as calibrators. Marginal differences in transcription levels between SHS-exposed and control mice were not statistically significant (Fisher’s exact test).