Fig. 7. Overexpression of GFP-PavDEAD results in failure of oocyte growth, loss of interfollicular stalks, fusion of egg chambers and formation of tubulin-actin aggregates. Wild-type (C,H) and mutant egg chambers expressing either GFP-PavDEAD (B,D,I) or GFP-PavNLS(4-7)^* (A,E-G) (green). DNA is in blue and Staufen (B), actin (C-G) and the Hu-li tai shao isoform ADD-60 (H-I) in red. (A) A linear projection of a series of confocal images of a germarium isolated from females expressing GFP-PavNLS(4-7)^*. The earliest visible GFP fluorescence appears in ring canals of cysts located in region 2a. The cyst located in region 2b contains 16 cells, whereas the stage 1 cyst in region 3 is composed of 32 cells. (B) A young egg chamber with its oocyte localised at the anterior pole (arrowhead). Asterisk, posterior pole. (C) Nurse cells of wild-type egg chamber accumulate actin at their cortex, facilitating the identification of their cell borders (arrowhead). Oocytes (OC) always have four associated ring canals and appear to have a higher concentration of actin at their cortex. They are in direct contact with the follicle cell (FC) layer (arrow). (D) Young mutant egg chambers are not separated by inter-follicular stalks (small arrow). Nurse cells still accumulate actin at their cell borders (arrowhead). The large arrow indicates that the oocyte (OC) is not in contact with the follicular cell layer. (E) A single follicle cell (FC) layer surrounds a 32-cell cyst with two oocytes (OC). All the nurse cells (NC) are of equal size. (F) A single follicle cell layer (FC) surrounds a 32-cell mutant egg chamber with two distinct cysts of 16 cells (1 and 2). Cyst 1 contains some collapsed ring canals (RC) and nurse cells that are not separated by an actin cytoskeleton (arrowhead). (G) An egg chamber in which tubulin-actin aggregates (arrow) are embedded in a cytoplasmic pool of microtubules. Nurse cell nuclei appear as black holes. (H) A wild-type egg chamber in which Hu-li tai shao is present in the ring canals (arrowhead). (I) Hu-li tai shao accumulates in the ring canals (arrowhead) and nurse cell membranes (arrow) of mutant egg chambers. Bars, 10 µm (A,E), 20 µm (C,D,F), 50 µm (G-I) and 100 µm (B).

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