Cox W G, Hemmati-Brivanlou A
Laboratory of Molecular Embryology, Rockefeller University, New York, NY 10021-6399, USA.
Development. 1995 Dec;121(12):4349-58. doi: 10.1242/dev.121.12.4349.
In order to study anteroposterior neural patterning in Xenopus embryos, we have developed a novel assay using explants and tissue recombinants of early neural plate. We show, by using region-specific neural markers and lineage tracing, that posterior axial tissue induces midbrain and hindbrain fates from prospective forebrain. The growth factor bFGF mimics the effect of the posterior dorsal explant in that it (i) induces forebrain to express hindbrain markers, (ii) induces prospective hindbrain explants to make spinal cord, but not forebrain and midbrain, and (iii) induces posterior neural fate in ectodermal explants neuralized by the dominant negative activin receptor and follistatin without mesoderm induction. The competence of forebrain explants to respond to both posterior axial explants and bFGF is lost by neural groove stages. These findings demonstrate that posterior neural fate can be derived from anterior neural tissue, and identify a novel activity for the growth factor bFGF in neural patterning. Our observations suggest that full anteroposterior neural patterning may be achieved by caudalization of prospective anterior neural fate in the vertebrate embryo.
为了研究非洲爪蟾胚胎前后神经模式的形成，我们开发了一种利用早期神经板外植体和组织重组体的新检测方法。通过使用区域特异性神经标记物和谱系追踪，我们发现后轴组织可诱导前脑原基产生中脑和后脑命运。生长因子碱性成纤维细胞生长因子（bFGF）模拟后背部外植体的作用，即（i）诱导前脑表达后脑标记物，（ii）诱导后脑原基外植体产生脊髓，而非前脑和中脑，以及（iii）在由显性负性激活素受体和卵泡抑素神经化而未诱导中胚层的外胚层外植体中诱导后神经命运。到神经沟阶段时，前脑外植体对后轴外植体和bFGF作出反应的能力丧失。这些发现表明后神经命运可源自前神经组织，并确定了生长因子bFGF在神经模式形成中的一种新活性。我们的观察结果表明，脊椎动物胚胎中通过将前神经原基尾化，可能实现完整的前后神经模式形成。
