EXPRESSION OF CONTACT, A NEW ZEBRAFISH DVR MEMBER, MARKS MESENCHYMAL CELL LINEAGES IN THE DEVELOPING PECTORAL FINS AND HEAD AND IS REGULATED BY RETINOIC ACID

Contact, a new zebrafish transforming growth factor-beta (TGF-beta) me mber is most closely related to mouse GDF5 and to human CDMP-1 respons ible, when mutated, for limb brachypodism phenotype and Hunter-Thompso n syndrome, respectively. Contact exhibits a dynamic spatial expressio n pattern in the pharyngeal arches and the pectoral fin buds that much prefigures cartilage formation. Within the fin buds, contact expressi on is detected in the proximal mesenchyme from which the endoskeleton will develop. Exogeneously applied retinoic acid (RA) induces duplicat ion of the pectoral fin rudiment in zebrafish embryos as well as conta ct expression along the proximal margin of the fin mesenchyme showing that both endoskeleton and exoskeleton can be duplicated. (C) 1997 Els evier Science Ireland Ltd.