dGcn5 is required for acetylation of histone H3 K9 and H3 K14 residues in polytene chromosomes. Polytene chromosomes from a Gcn5E333st/sex204 mutant and a lio-GAL4/UAS-H2b-YFP wild-type animal were squashed together and costained with DAPI (blue), anti-GFP (green), and an antibody (red) against acetylated H3 K14 (A), acetylated H3 K9 (C), acetylated H4 K8 (D), phosphorylated H3 S10 (E), dimethylated H3 K4 (F), dimethylated H3 K9 (G), or HP1 (H). Panels A and B show the same field through the red channel (acetylated H3 K14) and the green channel (H2b-YFP), respectively. The H2b-YFP signal in the green channel is not shown for immunostaining of the other histone modifications.