Figure 4.

TnI expression in mutant embryos. Dorsal view of whole mount embryos degoxygenin stained for TnI RNA expression in homozygous mutant genotypes for the indicated genes. Note the lack of TnI expression in somatic and visceral muscles in the mef2 null embryo, whereas tinman deficiency prevents expression in the heart and midgut only. Also, the biniou mutant prevents visceral expression only, whereas minc eliminates somatic expression. The dark signal observed in selected somatic muscle cells in the minc embryo (arrowhead) corresponds to an enhancer trap reporter within the dumbfounded gene that serves to mark the founder cells (Ruiz-Gomez et al., 2002).