Fig. 3. Expression of HDAC and histone acetylation in mouse oocytes. (A) Expression of HDAC activity in nuclei, cytoplasm and oocytes at the GV stage. The positive and negative controls were crude nuclear extract from MCF4 cells and were used according to the procedure outlined in the Cyclex HDAC assay kit. (B) Expression of HDAC activity in oocytes during maturation at various meiotic stages: GV (0 hours), GVBD (3 hours), MI (7 hours) and MII (17 hours). (C) Deacetylation of histone H3-K9 in somatic nuclei transferred into enucleated GV oocytes (a-h) or in control intact GV oocytes (i-l). Oocytes were cultured at various times to obtain the equivalent meiotic stages: GV-like stage (0 hours); GVBD (3 hours); MI-like stage (7 hours) and MII-like stage (17 hours). Scale bars: 20 µm.