Figure 3. Phosphorylation, methylation and acetylation of histone H3 and H4 contribute to IR-inducible miR-34a transcription. (A) Whole cellular lysate was prepared from IR-exposed HMEC cells at the indicated time-points post-irradiation; western blot analysis was performed using antibodies to phospho-histone H3 (Ser10), acetyl-histone H3 (Lys18), tri-methyl-histone H3 (Lys4), acetyl-histone H4 (Lys16), histone H3, histone H4 and actin. (B) Whole cellular lysate was prepared from IR-exposed HMEC cells in combination with different concentrations of SAHA 96 h post-irradiation; western blot analysis was performed using antibodies to acetyl-histone H3 (Lys18), acetyl-histone H4 (Lys16), histone H3, histone H4 and actin. (C) Total RNA was isolated from IR-exposed HMEC cells in combination with different concentrations of SAHA 96 h post-irradiation; quantitative real-time RT-PCR was performed using hsa-miR-34a primers. (D and E) HMEC cells grown to 50–60% confluency were exposed to either 30 kVp/0.1 Gy or 80 kVp/2.5 Gy X-ray; 96 h post-irradiation, cells were harvested; real-time ChIP-PCR and conventional ChIP-PCR were performed, as described in “Materials and Methods.” The asterisk indicates p < 0.05.