HISTONE H4 ACETYLATION IN DROSOPHILA - FREQUENCY OF ACETYLATION AT DIFFERENT SITES DEFINED BY IMMUNOLABELING WITH SITE-SPECIFIC ANTIBODIES

Electrophoresis, Western blotting and immunostaining with antibodies specific for histone H-4 acetylated at lysines 5, 8, 12, or 16, were used to define patterns of H-4 acetylation in cell lines from humans (HL60) and the fruit fly Drosophila (S2, Kc). In human cells, the mono-acetylated isoform H4Ac1 is acetylated predominantly at just one of the four possible lysine residues, lysine 16. This is the first step in the progressive acetylation of H-4. In contrast, in Drosophila, H4Ac1 is acetylated at lysines 5, 8, or 12 with approximately equal frequency. Fundamental differences appear to exist in control of H-4 acetylation in different species, despite the evolutionary conservation of acetylation sites.