title: Active signals, gradient formation and regional specificity in neural induction.
abstract: The question of how the vertebrate embryo gives rise to a nervous system is of paramount interest in developmental biology. Neural induction constitutes the earliest step in this process and is tightly connected with development of the embryonic body axes. In the Xenopus embryo, perpendicular gradients of BMP and Wnt signals pattern the dorsoventral and anteroposterior body axes. Both pathways need to be inhibited to allow anterior neural induction to occur. FGF8 and IGF are active neural inducers that together with BMP and Wnt signals are integrated at the level of Smad 1/5/8 phosphorylation. Hedgehog (Hh) also contributes to anterior neural induction. Suppressor-of-fused plays an important role in intertwining the Hh and Wnt pathways. Distinct mechanisms are discussed that establish morphogen gradients and integrate retinoic acid and FGF signals during posterior development. These findings not only improve our understanding of regional specification in neural induction, but have profound implications for mammalian stem cell research and regenerative medicine.
authors: Lund Stem Cell Center, BMC, B12, Klinikgatan 26, Lund University, S-221 84 Lund, Sweden. Electronic address: edgar.pera@med.lu.se.
authors: Edgar M
authors: EM
authors: Pera
authors: Lund Stem Cell Center, BMC, B12, Klinikgatan 26, Lund University, S-221 84 Lund, Sweden.
authors: Helena
authors: H
authors: Acosta
authors: Lund Stem Cell Center, BMC, B12, Klinikgatan 26, Lund University, S-221 84 Lund, Sweden.
authors: Nadège
authors: N
authors: Gouignard
authors: Lund Stem Cell Center, BMC, B12, Klinikgatan 26, Lund University, S-221 84 Lund, Sweden.
authors: Maria
authors: M
authors: Climent
authors: Lund Stem Cell Center, BMC, B12, Klinikgatan 26, Lund University, S-221 84 Lund, Sweden.
authors: Igor
authors: I
authors: Arregi
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D004627:Embryonic Induction; D005346:Fibroblast Growth Factors / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D009420:Nervous System / Q000196:embryology* / Q000378:metabolism*; D015398:Signal Transduction; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins; D051153:Wnt Proteins; D005346:Fibroblast Growth Factors
keywords: BMP; CNS; FGF; Hedgehog; HtrA1; IGF; Retinoic acid; Smad; Suppressor-of-fused; Wnt; Xenopus