Identification of RNA binding motif proteins essential for cardiovascular development

To determine the role of this gene in cardiac development, we have identified its zebrafish orthologs (rbm24a and rbm24b), and functionally evaluated them during zebrafish embryogenesis. Consistent with our underlying hypothesis, reduction in expression of either ortholog through injection of morpholino antisense oligonucleotides results in cardiogenic defects including cardiac looping and reduced circulation, leading to increasing pericardial edema over time. Additionally, morphant embryos for either ortholog display incompletely overlapping defects in the forming vasculature of the dorsal aorta (DA), posterior caudal vein (PCV) and caudal vein (CV) which are the first blood vessels to form in the embryo. Vasculogenesis and early angiogenesis in the trunk were similarly compromised in rbm24 morphant embryos at 48 hours post fertilization (hpf). Subsequent vascular maintenance was impaired in both rbm24 morphants with substantial vessel degradation noted at 72 hpf.Taken collectively, our functional data support the hypothesis that rbm24a and rbm24b are key developmental cardiac genes with unequal roles in cardiovascular formation.During vertebrate embryogenesis the heart is the first organ to develop and achieve functionality. Model organism studies have uncovered a number of genes such as Nkx2.5, which have important functions in early vertebrate myocardial development and differentiation [1,2]. Despite an increasing body of data illuminating the roles played by several key genes during cardiac development, there is still much to learn about what other factors may be critical. The general stages of cardiac development are invariable throughout vertebrate model organisms where heart development has been examined, with zebrafish progressing through these stages at a particularly rapid rate [3]. During zebrafish cardiogenesis the heart cone is the first structure to form between 19-20 hpf, followed by the formation of a short cardiac tube lacking discrete chambers by