Otte A P, Koster C H, Snoek G T, Durston A J
Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht.
Nature. 1988 Aug 18;334(6183):618-20. doi: 10.1038/334618a0.
Inductive cell interactions are essential in early embryonic development, but virtually nothing is known about the molecular mechanisms involved. Recently factors resembling fibroblast growth factor and transforming growth factor-beta were shown to be involved in mesoderm induction in Xenopus laevis, suggesting that membrane receptor-mediated signal transduction is important in induction processes. Here we report direct measurements of protein kinase C (PKC) activity in uninduced ectoderm, and in neuroectoderm shortly after induction by the involuting mesoderm, in Xenopus laevis embryos. Membrane-bound PKC activity increased three to fourfold in the induced neuroectoderm while the cytosolic PKC activity was decreasing, indicating that PKC activity was translocated during neural induction. A similar time- and dose-dependent translocation of activity was seen after incubation with the PKC activator 12-O-tetradecanoyl phorbol-13-acetate, which also induced neural tissue in competent ectoderm, suggesting that PKC is involved in the response to the endogenous inducing signal during neural induction.
诱导性细胞相互作用在早期胚胎发育中至关重要，但对于其中涉及的分子机制却几乎一无所知。最近，在非洲爪蟾中发现，类似于成纤维细胞生长因子和转化生长因子-β的因子参与中胚层诱导，这表明膜受体介导的信号转导在诱导过程中很重要。在此，我们报告了对非洲爪蟾胚胎中未诱导的外胚层以及内卷中胚层诱导后不久的神经外胚层中蛋白激酶C（PKC）活性的直接测量。在诱导的神经外胚层中，膜结合的PKC活性增加了三到四倍，而胞质PKC活性则在下降，这表明PKC活性在神经诱导过程中发生了易位。在用PKC激活剂12-O-十四烷酰佛波醇-13-乙酸酯孵育后，观察到了类似的时间和剂量依赖性活性易位，该激活剂也能在感受态外胚层中诱导神经组织，这表明PKC参与了神经诱导过程中对内源性诱导信号的反应。
