PROTEIN-TYROSINE KINASE-ACTIVITY DURING EGG ACTIVATION IS IMPORTANT FOR MORPHOGENESIS AT GASTRULATION IN THE SEA-URCHIN EMBRYO

Fertilization triggers a series of preprogrammed events functioning to activate egg metabolism, incorporate the paternal genome, and initiat e development. The activity of protein tyrosine kinases during egg act ivation is required for several steps leading up to the first cell div ision. We now present evidence for an additional protein tyrosine kina se-mediated event that occurs between 30 and 45 min after insemination and is not required until gastrulation, which occurs over 24 hr later . Eggs treated with protein tyrosine kinase inhibitors within this win dow of time cleaved and formed normal blastulae but could not gastrula te or undergo further development to the pluteus stage. These findings provide the first evidence that some of the control mechanisms used i n later development are established during a brief period of time in t he fertilized egg and require the action of one or more protein tyrosi ne kinases. (C) 1995 Academic Press, Inc.