Fig. 6. Defects in macrophage migration in Rac1, Rac2 and Mtl mutant embryos. All panels show stage 14 embryos double-labeled for anti-peroxidasin (green) to identify macrophages and anti-ß-Gal (red) to identify embryos that carry a TM6 balancer chromosome, carrying wild-type alleles of Rac1, Rac2 and Mtl. (A) Embryo expressing ß-Gal that was derived from a Rac1^J10 Rac2 mutant germline clone but is heterozygous for Rac1^J10 and Rac2 as it received a paternal copy of TM6. Macrophages show a normal distribution. (B) Homozygous Rac1^J10 Rac2 mutant embryo derived from a Rac1^J10 Rac2 germline clone. Macrophages have failed to populate the posterior trunk region (between arrows). (C) Homozygous Rac1^J10 Rac2 Mtl mutant embryo derived from a Rac1^J10 Rac2 Mtl germline clone. Again, macrophages have failed to populate the posterior trunk region (between arrows). Green labeling between arrows represents basement membrane staining by anti-peroxidasin antibody that is less prominent in A and B owing to variations in staining intensities. Bar, 100 µm.