Fig. 3. Disruption of the ovariole niche in germaria of orbit⁶ mutants. Germaria are stained with anti--spectrin (red), anti--tubulin (green) antibodies and TOTO3 (blue) to reveal DNA. (A) The apical region of a wild-type germarium with two stem cells (arrowhead) that each contains a spherical fusome (inferred by -spectrin staining). Germline cysts have branched fusomes (arrow) linked to microtubule bundles. (B) The germarium of a 1-day-old orbit⁶ female showing normal fusome morphology in a stem cell (arrowhead) and a germline cyst (arrow). In other cysts the fusome failed to branch (star). The terminal filament cells are not visible on the picture since they are out-of-focus. (C) The germarium of a 2-day-old orbit⁶ female that has no stem cells. Only one germline cell-cyst is present in the germarium containing a spherical fusome (star) and some fusome fragments. Microtubule bundles are cross-linking these fusome elements and the stack of terminal filament cells looks normal (arrow). (D) The germarium of a 3-day-old orbit⁶ female that has no stem cells. A single germline cell-cyst is present that contains a single nurse cell-like nucleus, an elongated fusome and some fusome fragments connected through microtubule bundles. A stack of terminal filament cells is not present. Scale bar: 10 µm.