ZFIN ID: ZDB-PUB-030408-4
Analysis of Wnt8 for neural posteriorizing factor by identifying Frizzled 8c and Frizzled 9 as functional receptors for Wnt8
Momoi, A., Yoda, H., Steinbeisser, H., Fagotto, F., Kondoh, H., Kudo, A., Driever, W., and Furutani-Seiki, M.
Date: 2003
Source: Mechanisms of Development 120(4): 477-489 (Journal)
Registered Authors: Driever, Wolfgang, Furutani-Seiki, Makoto, Kondoh, Hisato
Keywords: none
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Blotting, Northern
  • Cell Nucleus/metabolism
  • Cytoskeletal Proteins/metabolism
  • DNA, Complementary/metabolism
  • Genes, Dominant
  • In Situ Hybridization
  • Mesoderm/metabolism
  • Molecular Sequence Data
  • Mutation
  • Neurons/metabolism*
  • Phenotype
  • Protein Binding
  • Protein Structure, Tertiary
  • Proteins/genetics
  • Proteins/physiology*
  • RNA, Messenger/metabolism
  • Receptors, Cell Surface/genetics
  • Receptors, Cell Surface/physiology*
  • Receptors, Neurotransmitter/genetics
  • Receptors, Neurotransmitter/physiology*
  • Sequence Homology, Amino Acid
  • Signal Transduction
  • Time Factors
  • Trans-Activators/metabolism
  • Wnt Proteins
  • Zebrafish
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/physiology*
  • beta Catenin
PubMed: 12676325 Full text @ Mech. Dev.
ABSTRACT
The dorsal ectoderm of vertebrate gastrula is first specified into anterior fate by an activation signal and posteriorized by a graded transforming signal, leading to the formation of forebrain, midbrain, hindbrain and spinal cord along the anteroposterior (A-P) axis. Transplanted non-axial mesoderm rather than axial mesoderm has an ability to transform prospective anterior neural tissue into more posterior fates in zebrafish. Wnt8 is a secreted factor that is expressed in non-axial mesoderm. To investigate whether Wnt8 is the neural posteriorizing factor that acts upon neuroectoderm, we first assigned Frizzled 8c and Frizzled 9 to be functional receptors for Wnt8. We then, transplanted non-axial mesoderm into the embryos in which Wnt8 signaling is cell-autonomously blocked by the dominant-negative form of Wnt8 receptors. Non-axial mesodermal transplants in embryos in which Wnt8 signaling is cell-autonomously blocked induced the posterior neural markers as efficiently as in wild-type embryos, suggesting that Wnt8 signaling is not required in neuroectoderm for posteriorization by non-axial mesoderm. Furthermore, Wnt8 signaling, detected by nuclear localization of beta-catenin, was not activated in the posterior neuroectoderm but confined in marginal non-axial mesoderm. Finally, ubiquitous over-expression of Wnt8 does not expand neural ectoderm of posterior character in the absence of mesoderm or Nodal-dependent co-factors. We thus conclude that other factors from non-axial mesoderm may be required for patterning neuroectoderm along the A-P axis.
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