Fig. 6. Microtubule organization in wild-type oocytes and in rab11^P2148 GLCs. (A-F) Organization of microtubule minus ends in wild-type oocytes and in rab11^P2148 GLCs. Expression of tau-GFP in living stage 7 oocytes from wild-type (B) and rab11^P2148 GLC-bearing flies (E). Intense fluorescence at anterior cortex and the absence of fluorescence at the posterior pole indicate normal reorganization of the microtubule cytoskeleton in both oocytes, resulting in a concentration of microtubule minus ends at the anterior cortex. Immunolocalization of -tubulin in wild-type stage 8 oocytes (A) and in stage 8 rab11^P2148 GLCs (D). A distinct anterior-posterior gradient of microtubule density is seen in both oocytes, again indicative of normal microtubule minus end organization. In situ hybridization for bicoid (C) and gurken (F) transcripts in stage 10 rab11^P2148 GLCs. Both patterns are indistinguishable from that seen in wild-type controls (Saunders and Cohen, 1999; St Johnston, 1995). (G-I) Organization of microtubule plus ends in wild-type oocytes and in rab11^P2148 GLCs. Immunolocalization of Kin:ß-gal fusion protein in wild-type stage 9 oocytes (G) and in early (H) and late (I) stage 9 rab11^P2148 GLCs. The tight fluorescence at the posterior tip of the wild-type oocyte indicates sharp focusing of microtubule plus ends. Conversely, the expanded fluorescence along the lateral and posterior cortexes of rab11^P2148 GLCs indicates poor focusing of microtubule plus ends.