Fig. 1. Decreased level of ATAC-specific H4 acetylation results in reduced phosphorylation of histone H3 at S10. (A) Immunoblots of total protein extracts of wild-type (w¹¹¹⁸), dAda2a^d189, dAda2b^d842, dGcn5^E333st and JIL-1^z2 late third-instar larvae developed with antibodies specifically recognizing H4K12ac (top), and H4 (bottom). (B) Immunoblots of total protein extracts of wild-type (w¹¹¹⁸), dAda2a^d189, dGcn5^E333st and dAda2b^d842 late third-instar larvae developed with antibodies specific for H3S10ph (top), and for H3 (bottom). In A and B, the same membranes shown on the top were reprobed with H3- or H4-specific antibodies. (C) Double labeling with antibodies specific for H3S10ph (top) and for the C-terminal domain of the largest subunit of RNA polymerase 2 (Pol II 7G5; bottom) of polytene squashes from wild-type, dAda2a^d189, dAda2b^d842, dGcn5^E333st larvae. (D) Polytene chromosome squashes of dGcn5-null (dGcn5^E333st) third-instar larvae expressing a mutated dGcn5 transgene as indicated, double stained with antibodies specific for H3S10ph (top) and for the C-terminal domain of the largest subunit of RNA polymerase II (Pol II 7G5; bottom).