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Query: UNIPROT:O76050 (neu)
 3,969 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vertebrate neural development is initiated during gastrulation by the inductive action of the dorsal mesoderm (Spemann's organizer in amphibians) on neighbouring ectoderm, which eventually gives rise to the central nervous system from forebrain to spinal cord. Here we present evidence that bFGF can mimic the organizer action by inducing Xenopus ectoderm cells in culture to express four position-specific neural markers (XeNK-2, En-2, XIHbox1 and XIHbox6) along the anteroposterior axis. bFGF also induced the expression of a general neural marker NCAM but not the expression of immediate-early mesoderm markers (goosecoid, noggin, Xbra and Xwnt-8), suggesting that bFGF directly neuralized ectoderm cells without forming mesodermal cells. The bFGF dose required to induce the position-specific markers was correlated with the anteroposterior location of their expression in vivo, with lower doses eliciting more anterior markers and higher doses more posterior markers. These data indicate that bFGF or its homologue is a promising candidate for a neural morphogen for anteroposterior patterning in Xenopus. Further, we showed that the ability of ectoderm cells to express the anterior markers in response to bFGF was lost by mid-gastrula, before the organizer mesoderm completely underlies the anterior dorsal ectoderm. Thus, an endogenous FGF-like molecule released from the involuting organizer may initiate the formation of the anteroposterior axis of the central nervous system during the early stages of gastrulation by forming a concentration gradient within the plane of dorsal ectoderm.
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PMID:bFGF as a possible morphogen for the anteroposterior axis of the central nervous system in Xenopus. 755 36

Formation of mesoderm and posterior structures in early Xenopus embryos is dependent on fibroblast growth factor (FGF) signaling. Although several FGF receptors (FGFRs) are expressed in the early embryo, their respective role in these processes remains poorly understood. We provide evidence that FGFR-1 and FGFR-4 signals elicit distinct responses both in naive and neuralized ectodermal cells. We show that naive ectodermal cells expressing a constitutively active chimeric torso-FGFR-1 (t-R1) are converted into mesoderm in a Ras-dependent manner, while those expressing torso-FGFR-4 (t-R4) differentiate into epidermis without significant activation of Erk-1. In neuralized ectoderm, expression of t-R4 causes the up-regulation of the midbrain markers En-2 and Wnt-1, but not of the hindbrain nor the spinal cord markers Krox20 and Hoxb9. Mutation of tyr(776) in the phospholipase C-(gamma) binding consensus sequence YLDL of t-R4 completely abolishes En-2 and Wnt-1 induction. In contrast to t-R4, platelet derived growth factor (PDGF)-dependent FGFR-1 activation in neuralized ectodermal cells expressing a chimeric PDGFR-FGFR-1 receptor results in the expression of Krox20 and Hoxb9. A similar effect is observed when an inducible form of oncogenic Raf is expressed, therefore implicating FGFR-1 and Raf in the transduction of FGF-caudalizing signals in neural tissue. Our results suggest that FGFR-1 and FGFR-4 transduce distinct signals in embryonic cells, and mainly differ in their ability to activate the Ras/MAPK pathway.
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PMID:Signaling specificities of fibroblast growth factor receptors in early Xenopus embryo. 1091 Jul 71