Graves L M, Northrop J L, Potts B C, Krebs E G, Kimelman D
Department of Pharmacology SJ-30, University of Washington, School of Medicine, Seattle 98195.
Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1662-6. doi: 10.1073/pnas.91.5.1662.
Isolated explants from the animal hemisphere of Xenopus embryos were incubated with Xenopus basic fibroblast growth factor (XbFGF) or human activin A. XbFGF incubation resulted in the rapid activation of mitogen-activated protein kinase (MAPK) and ribosomal S6 protein kinase (pp90rsk) in a dose-dependent manner with the highest levels of activation occurring at 50 ng/ml. Maximal activation occurred within 6-10 min after the addition of growth factor, and the activity of both kinases declined to unstimulated levels after 30 min. Activin was unable to activate either MAPK or pp90rsk in the Xenopus explants to a substantial level, although it induced dorsal mesoderm better than XbFGF under the same experimental conditions. The regulatory protein Xwnt-8 did not activate MAPK, nor did it enhance the activation of MAPK by XbFGF. XbFGF was able to activate MAPK through at least the midgastrula stage, suggesting that this family of growth factors may have a role in gastrula-stage events.
将非洲爪蟾胚胎动物半球的分离外植体与非洲爪蟾碱性成纤维细胞生长因子（XbFGF）或人激活素A一起孵育。用XbFGF孵育导致丝裂原活化蛋白激酶（MAPK）和核糖体S6蛋白激酶（pp90rsk）迅速活化，呈剂量依赖性，最高活化水平出现在50 ng/ml时。添加生长因子后6 - 10分钟内出现最大活化，30分钟后两种激酶的活性降至未刺激水平。尽管在相同实验条件下激活素诱导背侧中胚层的效果优于XbFGF，但它在非洲爪蟾外植体中无法将MAPK或pp90rsk激活到显著水平。调节蛋白Xwnt - 8既不激活MAPK，也不增强XbFGF对MAPK的激活作用。XbFGF至少在原肠胚中期能够激活MAPK，这表明该生长因子家族可能在原肠胚期事件中发挥作用。
