Fig. 4. Translational control at egg-activation conferred on gnu by bcd3' UTR. (A) Immunoblot with anti-Gnu antibody of extracts from ovary (O) and embryo (E). w[1118]: Native Gnu in wild-type is mostly phosphorylated (slow mobility) in ovaries and dephosphorylated in embryos. gnu3': w;P{w⁺ gnuGFP}GG4C/+;gnu, the 55 kDa GnuGFP from the rescuing transgene with gnu 3' UTR was translated in ovaries and persisted in embryos. bcd3': w;P{w⁺ gnuGFP-bcd3'UTR}S2/+;gnu[+] ovaries contained no GnuGFP, but it was translated in embryos. (B) Consequence of Gnu expression on cyclins A and B. Immunoblots of homozygous gnu mutant ovaries (O) revealed reduced cyclin A and B expression, but embryos (E) from homozygotes had much lower levels than the w[1118] wild type. The P{w⁺ gnuGFP-bcd3'UTR} transgene restored cyclin A and B levels to embryos from w;gnu P{w⁺ gnuGFP-bcd3'UTR}T1 females but not to their ovaries. Anti-actin antibody was used to verify comparable protein loading on the blot.