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. 2003 Aug;23(16):5625–5637. doi: 10.1128/MCB.23.16.5625-5637.2003

FIG. 8.

FIG. 8.

Removal of dys function by dys-RNAi reveals tracheal fusion defects. Blastoderm embryos (w1118) were injected with either GFP-dsRNA (negative control) or dys-dsRNA and assayed for tracheal defects. (A) Stage 16 embryo injected with GFP-dsRNA and stained with α-Dys and MAb 2A12 that stains the tracheal lumen. Prominently shown is the lateral trunk, which has fused. Arrows point to lateral trunk Dys-positive fusion cells. The ganglionic branch (arrowhead GB) and lateral branch G (arrowhead LG), which emanates from the lateral trunk, are also indicated. (B) Stage 16 embryo injected with dys-dsRNA and stained with α-Dys and MAb 2A12. The embryo showed a lack of lateral trunk fusion (the asterisk indicates the normal location of a lateral-trunk fusion in wild-type or control embryos). Ganglionic Branch (GB) and lateral branch a (LG) are noted by arrowheads. No Dys-positive cells were observed, indicating that the dys-RNA effectively abolished Dys protein. (C to J) Second-instar larvae injected with either GFP-dsRNA or dys-dsRNA were examined by bright-field microscopy for tracheal defects. Sites of fusion are indicated by an arrow in control embryos. (C and D) Sagittal views showing the lateral trunk with ganglionic branches and lateral branch G. The dorsal trunk is also shown. The GFP-RNA larvae showednormal lateral trunk fusion (arrow) (C), but the dys-RNA larval lateral trunk failed to fuse (✽) (D). (E) Dorsal view showing the dorsal fusion site (arrow) of two dorsal branches in the GFP-RNA larva. (F) The dys-RNA dorsal branches migrate to the dorsal midline but fail to fuse (✽). (G and H) Ventral view showing the sites of ventral anastomosis of two pair of ganglionic branches. (G) In the GFP-RNA larva the arrow indicates the fusion of the two ganglionic branches indicated by arrowheads. (H) Fusion failed to occur (✽) in the dys-RNA larva. (I and J) Dorsal view showing that the dorsal trunks are fused in both GFP-RNA (I) and dys-RNA (J) larvae. The fusion site is indicated by arrows, and the lateral trunk branch is also labeled.