D. melanogaster Akt regulates Zw3 during early embryonic development. (A) Representation of the akt locus showing differential splicing of the three proposed isoforms (A, B, and C) and the site of insertion of the PZ P element (arrow). Coding regions are shown in red and untranslated regions are shown in blue (adapted from Flybase; http://www.flybase.indiana.org). (B) RT-PCR of a 400-bp region of the akt coding region from cDNA extracted from wild-type and akt mutant flies. (C) Western blot of 0–3-h embryo extracts probed with antibodies specific for Akt. CP190 is shown as a loading control. (D) Western blot of embryo extracts probed with an antibody specific for Zw3 phosphorylated on the consensus Akt phosphorylation site (Ser¹²). (E) Histogram demonstrating the rescue of akt1⁰⁴⁴²⁶ female sterility through the introduction of one copy of sgg¹. Error bars indicate the SEM.