FIG. 1.

dGcn5 is required for Drosophila metamorphosis. (A) Genetic map of the dGcn5 region. The Drosophila dGcn5 gene with its two introns (white boxes) is depicted in black. The deletion sex204 was generated by imprecise excision of the 1479/10 P element (black triangle) inserted in the CG14121 gene. dGcn5 alleles are indicated, as well as the position of the genomic fragment included in the PL transgenic construct. (B) Impaired metamorphosis in Gcn5^E333st mutants. (Left side) Homozygous Gcn5^E333st animals failed to formal normal puparium compared to Gcn5^E333st/TM3 control animals. Salivary glands from control or Gcn5^E333st late-third-instar larvae (top) were immunostained with a dGcn5 antibody. (Right side) Squashed salivary glands from wild-type (control) and homozygous Gcn5^E333st (E333st) late-third-instar larvae. Brackets indicate chromosomal regions corresponding to 2B (top) and 74EF-75B (bottom) early puffs, respectively. (C) Gcn5^E333st/Gcn5^C137T animals mostly died as pharate adults with abnormally elongated metathoracic legs (black arrowhead), strong defects in abdominal cuticle deposition (open arrowhead), and rough eyes. Note that the eye pigmentation was stronger in Gcn5^E333st/Gcn5^C137T animals than in Gcn5^C137T/TM3 control animals because of the presence of a FRT79D white⁺ marker on the mutagenized chromosomes. A metathoracic twisted and crooked leg (black arrow) from a Gcn5^E333st/Gcn5^C137T adult escaper is shown to the right. The same defects and lethality were observed for the Gcn5^E333st/Gcn5^ΔT280-F285 heteroallelic combination (not shown). (D) Structures of the wild-type and variant dGcn5 proteins expressed from pUAST-derived transgenic constructs. The N-terminal domain conserved in vertebrate Pcaf, the catalytic HAT domain, the Ada domain, and the bromodomain are indicated as shaded boxes.