We review the current status of research in dorsal-ventral (D-V) patterning in vertebrates. Emphasis is placed on recent work on Xenopus, which provides a paradigm for vertebrate development based on a rich heritage of experimental embryology. D-V patterning starts much earlier than previously thought, under the influence of a dorsal nuclear -Catenin signal. At mid-blastula two signaling centers are present on the dorsal side: The prospective neuroectoderm expresses bone morphogenetic protein (BMP) antagonists, and the future dorsal endoderm secretes Nodal-related mesoderm-inducing factors. When dorsal mesoderm is formed at gastrula, a cocktail of growth factor antagonists is secreted by the Spemann organizer and further patterns the embryo. A ventral gastrula signaling center opposes the actions of the dorsal organizer, and another set of secreted antagonists is produced ventrally under the control of BMP4. The early dorsal -Catenin signal inhibits BMP expression at the transcriptional level and promotes expression of secreted BMP antagonists in the prospective central nervous system (CNS). In the absence of mesoderm, expression of Chordin and Noggin in ectoderm is required for anterior CNS formation. FGF (fibroblast growth factor) and IGF (insulin-like growth factor) signals are also potent neural inducers. Neural induction by anti-BMPs such as Chordin requires mitogen-activated protein kinase (MAPK) activation mediated by FGF and IGF. These multiple signals can be integrated at the level of Smad1. Phosphorylation by BMP receptor stimulates Smad1 transcriptional activity, whereas phosphorylation by MAPK has the opposite effect. Neural tissue is formed only at very low levels of activity of BMP-transducing Smads, which require the combination of both low BMP levels and high MAPK signals. Many of the molecular players that regulate D-V patterning via regulation of BMP signaling have been conserved between Drosophila and the vertebrates.

中文翻译：

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爪蟾胚胎的背腹模式和神经诱导。

我们审查了脊椎动物的背腹（DV）模式研究的当前状态。重点放在非洲爪蟾的最新研究上，该研究基于丰富的实验胚胎学遗产，为脊椎动物的发展提供了范例。在背核-Catenin信号的影响下，DV图案的形成比以前想象的要早得多。在胚泡中部，在背侧有两个信号传导中心：预期的神经外胚层表达骨形态发生蛋白（BMP）拮抗剂，而未来的背内胚层分泌Nodal相关的中胚层诱导因子。当在腹腔形成背中胚层时，Spemann组织者会分泌生长因子拮抗剂的混合物，并进一步使胚胎形成图案。腹侧腹肌信号中心反对背组织者的动作，另一组分泌的拮抗剂在BMP4的控制下在腹腔产生。早期背侧-Catenin信号在转录水平抑制BMP表达，并促进前瞻性中枢神经系统（CNS）中分泌的BMP拮抗剂的表达。在中胚层不存在的情况下，前中枢神经系统的形成需要外胚层中Chordin和Noggin的表达。FGF（成纤维细胞生长因子）和IGF（胰岛素样生长因子）信号也是有效的神经诱导剂。通过抗BMP（如Chordin）进行神经诱导需要由FGF和IGF介导的促分裂原活化蛋白激酶（MAPK）活化。可以在Smad1级别上集成这些多个信号。BMP受体的磷酸化刺激Smad1转录活性，而MAPK的磷酸化具有相反的作用。仅在极低水平的BMP转导Smads活性下形成神经组织，这需要低BMP水平和高MAPK信号的结合。在果蝇和脊椎动物之间已经保存了许多通过BMP信号传导调节DV模式的分子。