Fig. 1. rab11 cloning and genetics. (A) Organization of the rab11 locus. The top line shows the 6.3 kb genomic rescuing fragment, the position of the P element insertion and the transcription start site and direction (arrow). The structure of the rab^ex1 and rab^ex2 excision alleles is shown below the rescue fragment, where the broken lines indicate uncertainties in the locations of the breakpoints. The rab11 transcription unit is shown at the bottom. Exons are depicted as rectangles, with the filled regions corresponding to protein coding segments. A, Asp718I; X, XhoI. (B) Developmental Northern blot showing rab11 expression throughout the fly life cycle. The control blot in the bottom panel was probed for Adh mRNA. RNA was prepared from the following tissues and stages: Ov, adult female ovaries; e, 0-24 h embryos; L1-L3, first, second and third instar larvae, respectively; m, adult males; f, adult females. (C) In situ hybridization for osk mRNA in rab11^P2148 and rab^ex1 GLCs. The absence of osk transcripts in rab^ex1 GLCs indicates that an oocyte is not determined. Similar results were obtained with rab^ex2 GLCs. (D) Western Blot with Rab11 antisera. Equivalent amounts of total ovarian protein from wild-type (WT) and rab11^P2148/rab⁺ flies (rab/+) were applied to each lane. A single major band of the expected size for Rab11 is detected in each lane.