Fig. 3. Expression of Shot proteins in tracheal cells during anastomosis. 1 µm confocal sections. (A-D) Stage 13 wild-type embryo undergoing anastomosis. (A) Anti-Shot labels a track in fusion cells (short arrow). Shot proteins (red in D) are cortically concentrated in other tracheal cells (concave arrow). The lumen (long arrow) is labeled nonspecifically (see E). (B) GAP43-GFP expression (green in D) in tracheal cells labels cell membranes. (C) esg-lacZ enhancer trap expression (blue in D) labels the fusion cells (short arrows) that bridge the two dorsal trunk branches. (D) Merge of A-C. (E-H) Stage 13, shot3. (E) Anti-Shot labels only the lumen (long arrow). (F) Tracheal cell membranes. (G) Fusion cells. (H) Merge of E-G. (I-L) Stage 15, wild type. Anastomosis is complete. (I) Shot is concentrated cortically in tracheal cells. Apically localized Shot cannot be distinguished from nonspecific lumenal staining. (J) Tracheal cell membranes. (K) Fusion cells are compact and encircle the lumen. (L) Merge of I-J. Scale bar: 10 µm.
