Planaria FoxA (HNF3) homologue is specifically expressed in the pharynx-forming cells

We have isolated a planarian Forkhead box A (FoxA, a new name for a gene group containing HNF3 alpha,beta,gamma)-related gene, DjFoxA, and examined its spatial and temporal distribution in both intact and regenerating planarians by in situ hybridization. In intact worms, DjFoxA is specifically expressed in the cells participating in pharynx development in the region surrounding the pharynx, which is located in the central portion of the body. During regeneration, DjFoxA-positive cells appear in the pharynx-forming region and migrate to the midline to form a pharynx rudiment. These results suggest that DjFoxA is specifically expressed in the cells participating in pharynx formation and has an evolutionarily conserved function in digestive tract formation.