.... At the blastula stage, the 32 cells of this lineage detach from the epithelium and ingress into the blastocoel by a process of epithelial-mesenchymal transition. We report that shortly before ingression,there is a transient and highly localized activation of the MAP-kinase ERK in the micromere lineage. We show...

... pole in embryos deprived from Tor activity. Anterior repression of Bcd targets was not observed in embryos lacking maternal contribution of D-sor , which acts downstream of Tor and encodes a MAP-kinase kinase. This indicates that the Ras signalling cascade is directly involved in this process, although...