Restraint of Fgf8 signaling by retinoic acid signaling is required for proper heart and forelimb formation

► Retinoic acid (RA) signaling regulates heart and forelimb development. ► We study the relationship of RA and FGF signaling. ► Increased FGF signaling mimics loss of RA signaling. ► Loss of RA signaling results in increased FGF signaling. ► FGF signaling acts downstream of RA signaling in heart and forelimb development.