Figure 3(a): SAHF formation. Representative microphotographs of B/CMBA.Ov cells prior to and post-treatment with 0.005 μM MIC at 48 h showing punctate DAPI-stained DNA foci in nuclei depicting senescence associated heterochromatin foci (SAHF) and increased levels of heterochromatin marker tri-methylated histone 3 at lysine 20 (H3K9Me) which colocalised with focal nuclear staining for DAPI (blue). While there are no typical changes in corresponding control. (b) SIPS associated hypo-acetylation of histone H4. Cells were treated with 0.005 μM MIC for 48 and 96 h. Immuno-blotting with antibody against pan-acetylated H4 (acH4) showed hypo-acetylation down the time points with maximum effect seen at 96 h. Blots represent mean of three independent experiments (n=3). β-actin was used as internal control.