Zebrafish aplnra functions in epiboly
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Updated: Jun 18, 2026

High Resolution Whole Mount In Situ Hybridization within Zebrafish Embryos to Study Gene Expression and Function
Published on: October 19, 2013
Svanhild Nornes1, Ben Tucker, Michael Lardelli
1Centre for the Molecular Genetics of Development and Discipline of Genetics, School of Molecular and Biomedical Science, The University of Adelaide, Australia. svanhild.nornes62@gmail.com
Background:
The zebrafish, Danio rerio, possesses the paralogous genes aplnra and aplnrb that are duplicates of an ancestral orthologue of the human APLNR gene encoding a G-protein coupled receptor that binds the peptide ligand APELIN and is required for normal cardiovascular function. aplnrb is required for migration of cells contributing to heart development in zebrafish embryos. aplnra is transcribed in a complex pattern during early development but its function in embryogenesis is largely unknown.
Findings:
Blockage of translation of aplnra mRNA in zebrafish embryos results in retarded or failed epiboly with the blastoderm apparently disconnected from the nuclei of the yolk syncytial layer. Gastrulation is also defective. Failure of correct tail extension is observed with ectopic structures resembling somites positioned dorsal to the spinal cord.
Conclusion:
aplnra, unlike its duplicate aplnrb, is essential for normal epiboly, although this function appears to be independent of signalling activated by zebrafish Apelin. The defects in epiboly caused by loss of aplnra activity appear, at least partially, to be due to a requirement for aplnra activity in the yolk syncytial layer.

