Fig. 6. Dizzy acts via Rap1 during the migration of macrophages. (A,B) The migration of macrophages is only slightly disturbed in zygotic rap1 mutant embryos. (A) In wild-type embryos, the macrophages are already found in the entire midline after stage 13. (B) The macrophages of zygotic, homozygous rap1 mutants fail to completely surround the midline of the VNC at stage 14 (arrowhead). (C) Confocal section of an embryo, highlighting the dorsal edge as shown in D-K. (D-K) Macrophages migrating along the dorsal edge. (D,E) Macrophages are not significantly affected in zygotic rap1 mutants. (F,G) Dizzy fails to induce cell shape changes in a rap1 mutant background. (H,I) Similarly, the even stronger cell shape phenotype induced by overexpression from two copies of dizzy^h.EP is rescued in rap1 mutants. (J) The expression of dominant-active Rap1^V12 induces a phenotype similar to 2xdizzy^h.EP. (K) Overexpression of wild-type Rap1 fails to induce cell shape changes in migrating macrophages. Embryos at stage 14.