The IRX1b gene presented here has been renamed IRX1a by Feijoo CG, Manzanares M, de la Calle-Mustienes E, Gomez-Skarmeta JL, Allende ML. 2004. The Irx gene family in zebrafish: genomic structure, evolution and initial characterization of irx5b. Dev Genes Evol 214:277–284.
Zebrafish IRX1b in the embryonic cardiac ventricle†
Article first published online: 20 OCT 2004
Copyright © 2004 Wiley-Liss, Inc.
Volume 231, Issue 4, pages 720–726, December 2004
How to Cite
Joseph, E. M. (2004), Zebrafish IRX1b in the embryonic cardiac ventricle. Dev. Dyn., 231: 720–726. doi: 10.1002/dvdy.20172
- Issue published online: 11 NOV 2004
- Article first published online: 20 OCT 2004
- Manuscript Accepted: 15 JUL 2004
- Manuscript Revised: 30 JUN 2004
- Manuscript Received: 17 MAR 2004
- National Institutes of Health
- American Physiological Society
- heart, cardiac;
- conduction system;
- Danio rerio;
The synchronous contraction of the vertebrate heart requires a conduction system. While coordinated contraction of the cardiac chambers is observed in zebrafish larvae, no histological evidence yet has been found for the existence of a cardiac conduction system in this tractable teleost. The homeodomain transcription factor gene IRX1 has been shown in the mouse embryo to be a marker of cells that give rise to the distinctive cardiac ventricular conduction system. Here, I demonstrate that zebrafish IRX1b is expressed in a restricted subset of ventricular myocytes within the embryonic zebrafish heart. IRX1b expression occurs as the electrical maturation of the heart is taking place, in a location analogous to the initial expression domain of mouse IRX1. The gene expression pattern of IRX1b is altered in silent heart genetic mutant embryos and in embryos treated with the endothelin receptor antagonist bosentan. Furthermore, injection of a morpholino oligonucleotide targeted to block IRX1b translation slows the heart rate. Developmental Dynamics 231:720–726, 2004. © 2004 Wiley-Liss, Inc.