Fig. 3. Developmental expression and post-translational modification. (A) Immunoblot with anti-peptide antiserum detected native Gnu protein in wild type (w[1118]) Drosophila ovaries (O) and 0-3 hour embryos (E) and detected functional Gnu-GFP fusion protein in ovaries from stock GG4c: homozygous gnu, rescued by a homozygous insertion of the genomic gnu-GFP construct (GG). (B) Expression in staged 0- to 4-hour embryos of Gnu (anti-Gnu) in w[1118] embryos (loading control: anti-actin), Gnu-GFP (anti-GFP) in GG4c embryos. (C-E) Functional fusion protein detected with anti-GFP antibody. (C) Proteins extracted from GG4c ovaries in the presence of the protein phosphatase inhibitors fluoride (NaF), orthovanadate (Na₃VO₄), ß-glycerophosphate (ßGP), okadaic acid (OA) and Inhibitor-2 (I-2Dm). (D) Extracts of ovaries, eggs and embryos from flies containing a single insertion of the genomic gnu-GFP construct in cortex (cort), grauzone (grau) and deadhead (dhd) mutant backgrounds or wild-type control homozygous for the genomic gnu-GFP construct. (E) Extracts of ovaries and embryos from flies containing a single heterozygous insertion of the genomic gnu-GFP construct in homozygous png backgrounds. png¹⁰⁵⁸ and png³³¹⁸ are null and weak alleles respectively. The wild-type control is from flies homozygous for the genomic gnu-GFP construct.