Abstract
Vitamin A plays a key role in a variety of biological processes in adults and is essential for normal embryonic development. Retinoic acid (RA), an oxidation product of vitamin A, plays complex and diverse roles during embryogenesis but both excess and lack of RA is a potent teratogen in rodents and humans. Since the discovery of RA receptors in 1980's, various mutant mice have been reported including RA receptors, RA binding protein, and RA synthesizing or degrading enzymes to elucidate functions during embryogenesis. I would summarize these phenotypes of mutant mice and refer how RA plays important roles during normal development, especially focusing on hindbrain, vertebra, and limb development.
