Orb isoforms are in different complexes.
(A). Ovary extracts were fractionated on 20–45% sucrose gradients. The fast phosphoisoforms are found in slowly sedimenting complexes in fractions near the top of the gradient. Based on the OD profile, these fractions are expected to contain 40S and 60S ribosomal subunits. The slow phosphoisoform are found in more rapidly sedimenting complexes distributed in fractions from the bottom two-thirds of the gradient. These fractions are expected to contain 80S particles and polysomes as indicated. (B) Ovary extracts (Ex) were immunoprecipitated with Bruno, Me31B, PABP, Wisp or β-galactosidase antibody in the presence of RNase A, and probed with Orb antibodies. First panel: Bruno (Bru), Orb, or β-gal antibodies were used for immunoprecipitation. Second panel: Me31B or β-gal antibodies were used for immunoprecipitation. Third panel: PABP or β-gal antibodies used for immunoprecipitation. Fourth panel: Wisp and β-gal antibodies used for immunoprecipitation. The amount of ovary extract (Ex) loaded is ∼10% of the amount of extract loaded in each immunoprecipitated sample.