COUP-TF - AN ORPHAN MEMBER OF THE STEROID THYROID HORMONE-RECEPTOR SUPERFAMILY/

COUP-TFs ave orphan members of the steroid/thyroid hormone receptor su perfamily. They ave transcription factors that are highly conserved ac ross species and have a wide spectrum of binding specificity. In tissu e cultures, COUP-TFs repress the transactivation function of several o ther members of the steroid/thyroid hormone receptor superfamily, and they also negatively regulate the transcription from promoters of many other genes. The expression profile of COUP-TFs in several species su ggests that they play an important role in development and differentia tion.