RETINOID X RECEPTORS AND COMPONENTS OF THE BASAL TRANSCRIPTION MACHINERY

摘要

The retinoid X receptor (RXR) participates in a wide array of hormonal signaling pathways either as a homodimer or as a heterodimer with other members of the steroid/thyroid hormone superfamily of receptors. In accordance with the present invention, the ligand-dependent transactivation function of RXR has been characterized and the ability of RXR to interact with components of the basal transcription machinery has been examined. In vivo and in vitro experiments indicate the RXR ligand binding domain makes a direct, specific and ligand-dependent contact with a highly conserved region of the TATA binding protein (TBP). The ability of mutations that reduce ligand-dependent transcription by RXR to disrupt the RXR-TBP interaction in vivo and in vitro suggests that RXR makes direct contact with the basal transcription machinery in order to achieve activation.