Fig. 3. rab11-null germline cysts arrest early and display defects in fusome segregation and bulk membrane trafficking. (A,B) Mosaic Drosophila germarium immunostained for (A) -Spectrin (red), Vasa (cytoplasmic green) and nGFP (green) or (B) E-cadherin (red), -Spectrin (blue) and nGFP (green). Severely affected rab11-null germline cysts with no detectable fusomes and reduced numbers of germline cells are outlined in yellow. A less affected rab11-null germline cyst with a normal fusome is outlined in white in A and indicated with an arrow in B. (C) Wild-type germarium immunostained for E-cadherin (red) and -Spectrin (blue). The arrowheads point to the posterior of the oocyte, where enriched accumulation of E-cadherin is evident, especially in the region 2B oocyte (left arrowhead). (D) Mosaic germarium immunostained for E-cadherin (red), -Spectrin (blue) and nGFP (green). The arrow points to a region 2B rab11-null oocyte with greatly reduced E-cadherin accumulation (compare with left arrowhead in C). The arrowhead points to a wild-type region 3 oocyte, where enriched E-cadherin expression is still apparent. A severely affected, rab11-null germline cyst, similar to those seen in B, is outlined. (E,E') Mosaic germarium immunostained for Orb (red, oocyte) and nGFP (green). The bracketed area in E is shown at a different focal plane in E'. Note that the oocyte is positioned at the posterior end of the wild-type germline cysts (arrowheads), but at the center of the rab11-null germline cyst (arrow). (F,G) Mosaic germarium immunostained for nGFP (green) and HtsRC (red) to label ring canals. (F) Left arrow points to a rab11-null germline cyst, with clumped ring canals. The right arrow points to a mosaic germline cyst, where the ring canals are only clumped in the rab11-null (GFP-negative) portion. (G) Germarium with a completely rab11-null germline. All ring canals are clumped in the center of the cysts. Scale bars: 10 µm.