Saint-Jeannet J P, Dawid I B
Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1994 Apr 12;91(8):3049-53. doi: 10.1073/pnas.91.8.3049.
The neural plate in the amphibian embryo is induced in the ectoderm by signals from the dorsal mesoderm. In the extensively studied species Xenopus laevis, such signals are believed to proceed along two alternate pathways, defined as vertical and planar induction. We have studied the relative importance of these pathways in Rana pipiens. In the embryo of this frog, dorsal mesoderm involution can be diverted from its normal course by injection of peptides that inhibit interaction of fibronectin with its receptor. In such embryos, dorsal mesoderm failed to migrate across the blastocoel roof but moved bilaterally along the equator, leading to the formation of two notochords. Neural tissue differentiation occurred in close association with each notochord, but no neural tissue formed along the dorsal midline as might have been predicted by a predominantly planar induction model. While in X. laevis planar induction has been reported to be a major pathway in neuralizing the ecoderm, the results presented here indicate that vertical induction predominates in initiating neural development in R. pipiens embryos.
两栖动物胚胎中的神经板是由来自背侧中胚层的信号在外胚层中诱导形成的。在广泛研究的非洲爪蟾物种中，此类信号被认为沿着两条交替途径进行，定义为垂直诱导和平板诱导。我们研究了这些途径在牛蛙中的相对重要性。在这种青蛙的胚胎中，通过注射抑制纤连蛋白与其受体相互作用的肽，可以使背侧中胚层内卷偏离其正常路径。在这类胚胎中，背侧中胚层未能穿过囊胚腔顶，而是沿赤道两侧移动，导致形成两条脊索。神经组织分化与每条脊索紧密相关，但正如主要的平板诱导模型所预测的那样，沿背中线没有形成神经组织。虽然在非洲爪蟾中，平板诱导已被报道是外胚层神经化的主要途径，但此处呈现的结果表明，垂直诱导在启动牛蛙胚胎的神经发育中占主导地位。
