Fig. 6. The effects of fog signaling on cell surface morphology. Scanning electron micrographs of Ore-R (A,C,E) and UASfog-expressing (B,D,F) embryos. Inset shows the rounded apical surface of cells in Ore-R and the apical flattening seen in 23% (n=21) of embryos expressing UASfog¹². (C,D) Embryos expressing the stronger line, UASfog⁶, show disrupted, irregular, delayed ventral furrow formation (VF) and regions of apical flattening (asterisk) compared with Ore-R. (E,F) At the onset of germband extension, cells that fail to be internalized round up (asterisk) and lateral folds appear (arrowheads) in UASfog⁶-expressing embryos.