ISOLATION OF A NOVEL RXR FROM XENOPUS THAT MOST CLOSELY RESEMBLES MAMMALIAN RXR-BETA AND IS EXPRESSED THROUGHOUT EARLY DEVELOPMENT

In a search for nuclear receptors that may mediate the teratogenic eff ects of the potential morphogen, retinoic acid, on the early developme nt of Xenopus we have isolated a novel Xenopus RXR that most closely r esembles the mammalian beta-type RXR. Xenopus RXR beta mRNA is express ed throughout early embryogenesis, and functions as an accessory prote in to enhance the DNA-binding of other members of the nuclear receptor superfamily.