Specification of an anterior neuroectoderm patterning by Frizzled8a-mediated Wnt8b signalling during late gastrulation in zebrafish.

Kim SH, Shin J, Park HC, Yeo SY, Hong SK, Han S, Rhee M, Kim CH, Chitnis AB, Huh TL
Development. 2002 129 (19): 4443-55

PMID: 12223403

Wnts have been shown to provide a posteriorizing signal that has to be repressed in the anterior neuroectoderm for normal anteroposterior (AP) patterning. We have previously identified a zebrafish frizzled8a (fz8a) gene expressed in the presumptive anterior neuroectoderm as well as prechordal plate at the late gastrula stage. We have investigated the role of Fz8a-mediated Wnt8b signalling in anterior brain patterning in zebrafish. We show that in zebrafish embryos: (1) Wnt signalling has at least two different stage-specific posteriorizing activities in the anterior neuroectoderm, one before mid-gastrulation and the other at late gastrulation; (2) Fz8a plays an important role in mediating anterior brain patterning; (3) Wnt8b and Fz8a can functionally interact to transmit posteriorizing signals that determine the fate of the posterior diencephalon and midbrain in late gastrula embryos; and (4) Wnt8b can suppress fz8a expression in the anterior neuroectoderm and potentially affect the level and/or range of Wnt signalling. In conclusion, we suggest that a gradient of Fz8a-mediated Wnt8b signalling may play crucial role in patterning the posterior diencephalon and midbrain regions in the late gastrula.

MeSH Terms (17)

Animals Body Patterning Brain Ectoderm Eye Gastrula Gene Expression Genes, Overlapping Gene Targeting Proteins Proto-Oncogene Proteins Receptors, Cell Surface Signal Transduction Wnt Proteins Xenopus Proteins Zebrafish Zebrafish Proteins

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