Fig. 7. Rab6 and BicD are in a complex and act together in Staufen localization at mid-oogenesis. (A) BicD co-immunoprecipitates specifically with Rab6 in ovarian extracts. Ovarian extracts of transgenic flies expressing Myc-tagged Rab6 or Rab7 were immunoprecipitated using a monoclonal anti-Myc antibody. Western blots were probed using anti-BicD or anti-Myc antibodies. (B) BicD and rab6 interact genetically in Staufen localization. The graph shows the percentage of stage-9 and -10 egg chambers of different genotypes displaying mislocalized Staufen. An average of 215 egg chambers per genotype were counted. Compared with rab6 single mutants, the proportion of egg chambers displaying defects in Staufen localization increases additively in rab6, par-1 double mutants, and synergistically in rab6, BicD double mutants. (C,D) Egg chambers stained for BicD (green), F-actin (phalloidin, red) and DNA (DAPI, blue). In wild-type egg chambers (C), after anterior migration of the oocyte nucleus (asterisk), BicD is detected between the oocyte cortex and the nucleus (C', arrow). In rab6^D23D egg chambers (D), BicD appears to be associated with the oocyte nucleus (D, asterisk), as in wild-type (D', arrow), and ectopically aggregates with ring canal clusters in nurse cell syncytia (D, arrowhead). I, input; U, unbound; B, bound.