Fig. 7. GFP-Aub localization is unlikely to be required for its role in translation. (A,B) Stage 8/9 egg chamber. Only a low level of GFP-Aub (A) is localized at the posterior pole of the oocyte (arrow), even though significant Osk protein (B) has already been translated. Note that the initial appearance of GFP-Aub at the posterior pole is not delayed by a time lag in acquiring fluorescence, as the aub mRNA is not itself localized and thus the protein is not synthesized at the posterior but is likely transported from existing pools elsewhere in the egg chamber. (C) Stage 9 egg chamber, with GFP-Aub concentrated at posterior of oocyte (right). Although Grk protein (not shown) is produced in the anterodorsal corner near the oocyte nucleus (arrow) at this stage, no localization of GFP-Aub is evident. The focal plane was chosen to emphasize the nucleus; the highest concentration of GFP-Aub at the posterior lies in a different plane. (D,E) Early embryos. Compared with control embryos produced by vas heterozygous females (D), little or no Osk protein remains at the posterior pole (right) of embryos from vas mutant females (E). No difference in Osk levels is detected in stage 10 oocytes (see Fig. 4), indicating that the defect of vas mutants in translation of Osk begins only late in oogenesis.
