Exploring the molecular link between swim-training and caudal fin development in zebrafish (Danio rerio) larvae

Summary In vitro and in vivo studies have shown that mechanical forces play an important role during development. The molecular mechanisms via which mechanical forces regulate development have been extensively investigated by in vitro studies. However, knowledge about the molecular pathways that mediate the effect of mechanical forces during development in vivo is limited. Previously, we showed that swim‐training increased maximum normalized curvatures in the caudal fin (suggesting that the caudal fin experienced increased mechanical loads) and prioritized the development of skeletal structures in the caudal fin. Therefore, we used the zebrafish caudal fin to explore the molecular link between an increased swimming activity and development in vivo. Whole genome microarray analysis of caudal fins of zebrafish subjected to swim‐training and control fish identified 46 genes which were up‐regulated with a fold change of 1.5 or larger at 10 dpf. Fourteen genes were expressed specifically in the following tissues in the caudal fin: the neural tube, the tissue surrounding the hypurals, the finfold, or muscle fibers. Subsequently, we identified two muscle specific genes, aste1 (asteroid homolog 1) and zgc:65811, which showed an increased expression specifically in the caudal fin in response to swim‐training. This makes these genes interesting candidate genes for further research on the molecular link between mechanical forces and caudal fin development. Our study is the first to investigate the molecular link between swim‐training and caudal fin development and offers a system that can provide a deeper understanding of the link between mechanical and molecular signals during development in vivo.