Fig. 3. Activation of MAPK and rescue of Eve-positive cells in the mesoderm of htl mutants. Embryos were stained with antibodies directed against dp-ERK (left), or Even-skipped (right). (A,H) Whole-mounts of wild-type embryos; (B-G,I-N) enlarged views of the trunk regions of htl mutant embryos. (B,I) The homozygous htl mutant phenotype. (C-G,J-N) The effect of expressing transgenes in the mesoderm of htl mutant embryos. (C,J) Htl; (D,K) an activated form of Htl; (E,L) an activated form of Btl; (F,M) an activated form of EGFR; (G,N) an activated form of PVR.