Fig. 6. The function of PBL in mesoderm migration is mesoderm autonomous. Embryos hemizygous for pbl³, expressing twi::Gal4, UAS::pbl^3.2 were stained with anti-NRT (red) and anti-TWI (green) antibodies and sectioned. Embryos are shown in phase 1 (A), phase 2 (B) and phase 3 (C) of migration. A complete rescue of cell shape change defects in pbl mutants is seen. Note that cytokinesis is occurring normally in the mesoderm while still blocked in the ectoderm (insert in B; the asterisks mark nuclei). (D,E) Differentiation of EVE-positive mesoderm cells is rescued by expression of UAS::pbl^3.2 with twi::Gal4 in pbl³ hemizygously mutant embryos. (D) Stage 11 embryo containing at least one wild-type copy of the pbl gene; the blue staining indicates presence of the TM3 (ftz::lacZ) chromosome. (E) Stage 11 embryo of the genotype twi::Gal4/UAS::pbl^3.2; pbl³/Df(3L)pbl^NR.