Fig. 1. Rab5 is required for endocytosis in the Drosophila oocyte. (A) Schematic representation of a stage 9 egg chamber. Anterior is up, posterior is down. (B-E) Yolk protein internalization in control (B,D) and in rab5² GLC (C,E) stage 10 oocytes. (B,C) GFP autofluorescence; (D,E) Yolk autofluorescence. (C) The absence of nuclear GFP in the germline cells marks the presence of a GLC. (D,E) In rab5² GLCs, no yolk granule autofluorescence was visible (E) when compared with control oocytes (D). (F,G) Quantification of autofluorescence along the broken line in D and E. Note that, unlike in the control, there is no detectable increase in autofluorescence intensity in the rab5² oocyte (o) when compared with the adjacent follicle cells (fc), which are heterozygous for rab5² in both cases. (H,I) Yl localization in wt control (H) and in rab5²-GLCs (I) at stage 9. Blue, DNA; red, Yl. In rab5²-GLCs, Yl is found in abnormal cytoplasmic compartments (arrows in I) and, as in control (J), at the oocyte PM. Scale bars: 50 µm.