Fig. 5. Early germ cells accumulate in stet mutant germaria. (A) Diagram of a wild-type germarium. Germ cells in dark gray, somatic cells in light gray. Note spectrosomes (sp) in germline stem cells (gsc) and cystoblasts (cb) in region 1, and branched fusomes (fu) in cystocytes (cys). In region 1 and 2A, germ cells are surrounded by cytoplasmic extensions (light gray) from inner sheath cells (isc). In region 2B, germ cells become enclosed by somatic follicle cells (fc). Region 3 contains one egg chamber. Terminal filament cells (tfc), cap cells (cc), follicle precursor cells (fpc), as indicated. (B,H) Scale bars: 5 µm. (B-G) Germaria from (B,D,F) wild-type and (C,E,G) stet mutant females; apical tips towards the left. (B,C) Immunofluorescense staining with anti-Sxl. (B) Wild type: stem cells and cystoblasts at the tip have high level of cytoplasmic Sxl (arrow). (C) stet: many early germ cells with high level of cytoplasmic Sxl (arrows). (D,E) Immunofluorescense staining with anti--spectrin. (D) Wild-type: -spectrin in spectrosome (arrows) in stem cells and cystoblasts and the branching fusome (arrowhead) in cystocytes. (E) stet: many cells with spectrosomes (arrows). (F,G) Expression of UAS-GFP under control of the en-GAL4 activator in inner sheath cells in region 1 and 2A. (F) Wild type: extensions from inner sheath cells extend among germ cells in region 1 and 2A (arrows). (G) stet: inner sheath cells are present and express GFP (arrows), but no cytoplasmic extensions were detected. (H) Electron microscope image showing a cytoplasmic extension (arrowheads) originating from an inner sheath cell (n, nucleus of inner sheath cell) and extending between a germline stem cell (s) and a cystoblast (c). Cap cell (cc), spectrosome (sp), as indicated. The image was taken by A. T. Carpenter from the wild-type germarium analyzed by Carpenter (Carpenter, 1975).

Return to article