Fig. 5. F-actin accumulation in DME-cells during dorsal closure. Embryos were collected at times indicated. Arrows indicate the leading edge. (A) In wild type, leading edge signals of F-actin increased gradually during 9-11 hours AEL. Src42A^26-1;Src64^P1/+ embryos exhibited almost normal F-actin deposition at 9 hours AEL, but, at later stages, leading edge F-actin was reduced significantly. Src42A^26-1 embryos were almost normal in F-actin deposition at the leading edge (B4). In shg^R64a mutants (B1-B3), thick accumulation of F-actin at leading edge disappeared at 10 hours AEL. (C1-C3) Change in dpp expression at leading edge. dpp expression, which is under the control of the JNK signaling (Goberdhan and Wilson, 1998), was monitored using nuclear enhancer trap (dpp-lacZ). In Src mutants, dpp expression has ventrally expanded as in the case of puc mutants (Martin-Blanco et al., 1997). (D1-D3) Effects of shg activity on Src42A distribution. shg^R69 clone on pupal wing disc was marked by the absence of lacZ signals (green). In the shg^R69 clone, Src42A signals (magenta) in plasma membrane were significantly reduced. Merged picture is on the left.