Fig. 6

Histone H4 isoforms altered in leukemic and cancer cells. a A representative histone H4 LC/MS spectrum. The peaks that are significantly changed in CLL, bladder and breast cancer cells are highlighted with arrows (CLL-green, bladder-red and breast-blue). b–d Representative spectrum (b) and histograms representing the relative abundance of the peaks with molecular weight ~11,390 Da (c) and ~11,406 Da (d) in bladder cancer cells. The relative abundance of each isoform has been determined as described in Fig. 2b. e–g Representative spectra (e) and histograms representing the relative abundance of the peaks with molecular weight ~11,306 Da (f) and ~11,348 Da (g) respectively in breast cancer cells. h Western blot analysis of histones isolated from the M1–M4 cell lines (as indicated). Western blots were probed with antibodies recognizing the indicated sites of acetylation on the NH₂-terminal tail of histone H4. The bottom panel shows the Ponceau S staining of the blot prior to antibody incubation