Fig. 2. Grk is mislocalized to post-Golgi compartments in Drosophila Rab6 mutants. (A,B) Low magnification electron micrographs of control (A) and rab6^D23D mutant (B) egg chamber. (A',A'') Magnified view of boxed area from A. (B',B'') Magnified view of boxed area from B. nc, nurse cells; oo, oocyte; fc, follicle cells. ER morphology in control (arrows in A') and in rab6^D23D (arrows in B'). Normal tER-Golgi unit morphology in the control (A'') and onion-like shaped morphology in mutant (B''). Cisternae (arrowheads) were not altered in number, although severely swollen, in the mutant. (C) Drab6 and Grk colocalization in GFP-Drab6-rescued oocyte. (D,E) Projection of optical sections (20 µm) of control (D) and rab6^D23D (E) stage 9 oocytes, stained for Grk and F-actin. Upper insets, confocal sections at the nucleus. Lower insets, control egg and ventralized egg in the mutant. In contrast to the control, Grk formed larger particles close to and ring-like structures remote from the nucleus (arrowhead) in the mutant. (F,G) Grk and Lva colocalized marginally to small particles close to the nucleus in the control (F) and in rab6^D23D (G) oocytes. Colocalization was not observed for the large Grk-positive ring-like structures (G, arrowheads in enlarged view shown in inset) in the mutant. (H,I) Control and Drab6 mutant egg chamber, respectively, labeled with Grk and LysoTracker (Lyso) to reveal endosomal compartments and lysosomes. (H',I') Magnified view of upper boxed area from H and I, respectively. (H'',I'') Magnified view of lower boxed area from H and I, respectively. Grk colocalized in a ring-like manner with Lyso-positive structures close to and distal to the nucleus only in rab6^D23D. Asterisk, oocyte nucleus. Scale bars: 20 µm; 500 nm in B''.