Developmentally regulated expression of a mitogen-activated protein kinase in Xenopus laevis.
Mitogen-activated protein (MAP) kinases are activated in somatic cells in response to many extracellular stimuli and in oocytes during meiotic maturation. We have examined the tissue specificity of expression of a MAP kinase (Xp42) in adult and larval Xenopus laevis. MAP kinase RNA and protein were abundant in the nervous system and lymphoid tissues and were readily detected in most other organs. A remarkably high level of RNA was detected in ovary. Fractionation of oocytes showed that MAP kinase RNA is expressed at the highest level in small oocytes, suggesting that it is a maternal RNA that is stored for early embryogenesis. The levels of MAP kinase RNA and protein did not change from the time of fertilization through to late blastula. The results are consistent with functions for MAP kinases in signal transduction in embryonic as well as adult cells.
Zaitsevskaya
T
T
Fred Hutchinson Cancer Research Center, Seattle, Washington 98104.
Cooper
J A
JA
D000818:Animals; D004625:Embryo, Nonmammalian / Q000201:enzymology; D004790:Enzyme Induction; D007814:Larva; D008221:Lymphoid Tissue / Q000201:enzymology; D019950:Mitogen-Activated Protein Kinase 1; D009124:Muscle Proteins / Q000096:biosynthesis; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D009865:Oocytes / Q000201:enzymology; D009866:Oogenesis; D009928:Organ Specificity; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction; D012867:Skin / Q000201:enzymology; D014781:Viscera / Q000201:enzymology; D014982:Xenopus laevis / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism
D009124:Muscle Proteins; D009419:Nerve Tissue Proteins; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1