Zebrafish Bone and Vascular Growth

Abstract To better investigate the vascular network in zebrafish, a transgenic line was developed in zebrafish expressing EGFP driven by a promoter for <em>fli1 </em>which is expressed during vascular development in zebrafish embryos. The first exon of <em>fli1 </em>was incorporated into zebrafish, which proved to be sufficient in driving expression within the blood vessels of embryos (Lawson, 2002). The simple composition of the caudal fin, high regenerative capacity of zebrafish and the <em>fli1</em> promoter allows for in depth investigation of the vascular network. Development and regenerative growth is mediated by a variety of factors, including connexins, adhesion molecules and ligands. Inhibition of calcineurin results in outgrowth of regenerating fins, suggesting the regeneration rate is at its highest when calcineurin is low (Kujawski, 2014). FK506 (tacrolimus) is a commonly used immunosuppressant in organ transplant. FK506 binds to FK506 binding protein, an immunophilin, forming a complex that suppresses the activation of the calcineurin-dependent NFAT pathway and calcineurin-independent pathway for JNK. The goal of this experiment is to understand the role calcineurin plays in the development of both bone growth and vessel growth, using <em>danio rerio</em>, as an <em>in vitro</em> model. Calcineurin inhibition has been shown to play a role in the developing fin, presumably influencing the underlying vasculature as well. In order to elucidate this role, calcineurin manipulation will be introduced into the zebrafish model. The vasculature differences will be observed as a measure of its' role, and recorded to prove a concise function for calcineurin in bone and vessel growth.