Fig. 7. Possible role of TC14-3 in asexual reproduction of P. misakiensis. (A) The atrial epithelium is composed of differentiated pigment cells. (B) During blastogenesis, dedifferentiation takes place. (C) Dedifferentiated cells become progenitors of various tissues and organs. (D) Respective progenitor cells enter the terminal differentiation pathways to become nerves, gastric epithelium, pharyngeal epithelium and others. TRAMP is a retinoic acid-inducible serine protease that promotes cell growth and, possibly, dedifferentiation of the atrial epithelium. TC14-3 is expressed constitutively by mesenchymal cells and by the atrial epithelium during budding stages. It blocks cell growth, dedifferentiation and the resultant terminal differentiation of the atrial epithelium, thus contributing to the maintenance of multipotent cells. The effect of TC14-3 is strong but reversible, as it is cancelled with ease by galactose.
