PROTEIN-KINASE-C ISOZYMES HAVE DISTINCT ROLES IN NEURAL INDUCTION AND COMPETENCE IN XENOPUS

The restricted ability of embryonic tissue to respond to inductive signals is controlled by a poorly understood phenomenon, termed competence. In Xenopus, dorsal ectoderm is more competent than ventral ectoderm to become induced to neural tissue. We tested whether the Xenopus protein kinase C (PKC) isozymes-alpha and beta have a role in neural induction and competence. We found that PKC-alpha is predominantly localized in dorsal ectoderm, whereas PKC-beta is uniformly distributed. Overexpression of PKC-beta conveys a higher propensity for neural differentiation to both dorsal and ventral ectoderm, but their difference in competence remains. However, ectopic expression of PKC-alpha elevates the level of neural competence of ventral ectoderm to that of dorsal ectoderm. These data indicate that different PKC isozymes have distinct roles in mediating both neural induction and competence.