Fig. 1. Summary of signaling and transcriptional pathways during the induction of trunk visceral mesoderm. Shown are three parasegments of the mesoderm (divided into P and A domains) (Azpiazu et al., 1996) of a stage 10 embryo stained for bap mRNA (purple) and Eve protein (brown). The expression domains of Tin (schematically shown in blue) and the relevant Slp domains (red) are within the mesoderm, whereas Dpp (yellow) and Wg (brown) are secreted from the overlying ectoderm. Inductive signals are represented by hatched arrows and transcriptional interactions are represented by solid arrows.