MAP kinase is activated during mesoderm induction in Xenopus laevis.
MAP kinase (MAPK) is activated in animal cap explants from Xenopus embryos in response to mesoderm induction by FGF. This activation is rapid, appearing within 1 min of treatment with FGF, and prolonged, lasting for at least 2 hr. By immunoblot analysis, this activation of MAPK is coupled with an electrophoretic shift to the slowly migrating, phosphorylated form of MAPK. Activin-stimulated mesoderm induction also results in the activation of MAPK, but only upon prolonged exposure. However, activin can potentiate the activation of MAPK by FGF as early as 1 min after administration. These findings suggest that MAPK is involved in the early signaling events of FGF-mediated mesoderm induction, and this involvement is modulated by other mesoderm inducers such as activin.
Hartley
R S
RS
Howard Hughes Medical Institute, University of Colorado School of Medicine, Denver 80262.
Lewellyn
A L
AL
Maller
J L
JL
D000595:Amino Acid Sequence; D000818:Animals; D004627:Embryonic Induction; D004789:Enzyme Activation; D005306:Fertilization; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1; D008969:Molecular Sequence Data; D010063:Ovum / Q000201:enzymology; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology*
D010455:Peptides; D016222:Fibroblast Growth Factor 2; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1