Figure 4. Effects of melatonin on global genomic DNA methylation and DNMT expression in prolonged-culture oocytes. Porcine oocytes matured in vitro were continuously cultured in medium supplemented with or without 10−3 M melatonin for 24 h. (A) Representative images of fresh, prolonged-culture, and prolonged-culture + Mel oocytes stained with 5mc antibody. (B) Quantitative analysis of 5mc ﬂuorescence intensity. (C) Expression of DNMT1, DNMT3A, and DNMT3B in fresh, PC, and PC + Mel oocytes. The data are presented as the mean ± SEM of at least three independent experiments. Scale bar=100 μm; PC, prolonged-culture; Mel, melatonin; **P<0.01, *** P<0.001, **** P<0.0001.