ZFIN ID: ZDB-PUB-050913-5
hecate, a zebrafish maternal effect gene, affects dorsal organizer induction and intracellular calcium transient frequency
Lyman Gingerich, J., Westfall, T.A., Slusarski, D.C., and Pelegri, F.
Date: 2005
Source: Developmental Biology   286(2): 427-439 (Journal)
Registered Authors: Pelegri, Francisco, Slusarski, Diane C.
Keywords: Wnt signaling, B-catenin, Calcium, hecate, Axis induction, Maternal effect, Zebrafish
MeSH Terms:
  • Animals
  • Calcium/metabolism*
  • Choristoma/genetics*
  • Gene Expression Regulation, Developmental
  • Mutation*
  • Organizers, Embryonic/embryology*
  • Wnt Proteins/metabolism
  • Zebrafish/embryology*
  • beta Catenin/metabolism
PubMed: 16154557 Full text @ Dev. Biol.
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ABSTRACT
A zebrafish maternal effect mutation, in the gene hecate, results in embryos that have defects in the formation of dorsoanterior structures and altered calcium release. hecate mutant embryos lack nuclear accumulation of β-catenin and have reduced expression of genes specific to the dorsal organizer. We found that hecate mutant embryos exhibit a nearly 10-fold increase in the frequency of intracellular Ca(2+) transients normally present in the enveloping layer during the blastula stages. Inhibition of Ca(2+) release leads to ectopic expression of dorsal genes in mutant embryos suggesting that Ca(2+) transients are important in mediating dorsal gene expression. Inhibition of Ca(2+) release also results in the expression of dorsal-specific genes in the enveloping layer in a β-catenin-independent manner, which suggests an additional function for the Ca(2+) transients in this cellular layer. The mutant phenotype can be reversed by the expression of factors that activate Wnt/β-catenin signaling, suggesting that the Wnt/β-catenin pathway, at least as activated by an exogenous Wnt ligand, is intact in hec mutant embryos. Our results are consistent with a role for the hecate gene in the regulation of Ca(2+) release during the cleavage stages, which in turn influences dorsal gene expression in both marginal cells along the dorsoventral axis and in the enveloping layer.
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