Fig. 3. Polarized distribution of Rbsn-5 and endosomal proteins in developing Drosophila oocytes. (A,B) Double staining of wild-type oocytes for Rbsn-5 (green) and Stau (magenta). Both Rbsn-5 and Stau were concentrated at the center of stage 7 oocytes (A, arrowhead). From stage 8 onward, both signals were restricted to the posterior pole of the oocytes (B). An enlarged image of the bracketed region is shown in the right panel. (C-H) Distribution of endosomal proteins (Rab5, Rab11 and Rab7) in wild-type oocytes. All endosomal proteins showed transient accumulation at the center of stage 7 oocytes and posterior enrichment in late-stage oocytes (arrowheads). (I-L) Double staining of wild-type ovaries for Stau (magenta) and ER (I,J) or Golgi apparatus (K,L) markers (green). DNA was counterstained with DAPI (cyan) in all images. Scale bars: 20 µm.