Figure 3.

Transcriptional activity assay at the two-cell stage in parthenogenetic embryos treated with FK228 and other HDAC inhibitors. (A) Scheme of the transcriptional activity assay using parthenogenetic embryos. 5-EU was added to the medium at 5 h after activation and the embryos were cultured until 24 h. Nascent RNA transcription during the major zygote gene activation (ZGA) phase at the two-cell stage was measured by incorporation of EU detected by specific fluorescence. (B) Representative images of fluorescence specific for incorporated EU in control and HDAC inhibitor-treated parthenogenetic embryos. Bar = 20 μm. (C) Relative fluorescent intensity for incorporated EU (see Materials and methods). Each dot represents one nucleus (two nuclei per embryo). The fluorescence level of the FK228-treated embryos was significantly lower that of the embryos treated with other HDAC inhibitors (P < 0.0001 by Tukey test).