Fig. 5. Deposition of the apical surface determinant Dlt along the Shot/F-actin track. (A-T) Stage 13, wild-type embryos. (A-E) Dlt (red) accumulates in fusion cells along a track (arrows) containing Shot-GFP (green) and F-actin (blue). (F-J) Dlt is detected along the track after the track forms (compare G with H). Dlt concentration is initially lower in fusion cells along the apical surface connecting the existing lumens (I); it then accumulates in three rings (J, inset) at the anastomosis site (arrow). (K-O) Accumulation of Shot-GFP in fusion cells. (P-T) Formation of the F-actin track in fusion cells (P-R) and its association with new apical surface (S,T). Scale bar: 10 µm (5 µm for inset).