Objective To establish a model of retinal dehydrogenase type 2(raldh2) gene knock-down zebrafish embryos,and to explore the effect of insufficient retinoid acid(RA) signaling on the early embryonic cardiac development,especially on the regulation of cardiac development-related nppa and tbx20 gene expression.Methods A morpholino antisense oligonucleotides(MO) targeting zebrafish raldh2 gene was designed to knock down its expression and constructed a raldh2-EGFP plasmid to verify the effectiveness and specifi...