Fig. 5. Loss of RhoA function affects puc expression. (A) Lateral view of an embryo carrying the puc^E69 enhancer trap, stained with rhodamine-phalloidin to detect F-actin and anti-ß-gal antibody to detect puc expression. In wild-type embryos, puc expression is strictly limited to the single row of leading edge cells. (B-D) Embryos carrying the puc^E69 enhancer trap and expressing RhoA^N19 in enGAL4 stripes, stained as above. (B) Dorsal view showing that, although the leading edge is ragged, puc expression occurs along its entire length. In some places, however, puc expression is seen away from the leading edge. (C) High-magnification view showing stripes of RhoA^N19 expression (indicated by white bars and detected by abnormal actin organization, arrow) in which either cell rearrangement (stripes marked by an asterisk) or ectopic puc expression results in cells lateral to the leading edge being positive for ß-gal staining. (D) Ectopic expression of puc is also detected within cells of the ventral epidermis.