RETINOID-X RECEPTOR-ALPHA TRANSACTIVATES THE HEPATITIS-B VIRUS ENHANCER-1 ELEMENT BY FORMING A HETERODIMERIC COMPLEX WITH THE PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR
The hepatitis B virus enhancer 1 contains a retinoic acid responsive element (RARE). We have previously demonstrated that retinoid X receptor alpha (RXR alpha) transactivates enhancer 1 by binding to the RARE. The present study has revealed that a heterodimeric complex composed of RXR alpha and peroxisome proliferator-activated receptor (PPAR) interacts with the hepatitis B virus RARE. Transient transfection studies in conjunction with in vitro DNA binding data, support the hypothesis that the RXR alpha-PPAR heterodimer transactivates enhancer 1.