Mutational analysis of enhancer domains responsive to trans-activation by the X gene of human hepatitis B virus

Abstract
The X gene product of human hepatitis B virus (HBV) trans-activates the HBV enhancer. In order to identify domains responsive to trans-activation by the X gene, we introduced a series of mutations into the HBV enhancer and assayed the enhancer activities in the presence of the X gene product. Our results suggest that the EP domain of the enhancer is essential for trans-activation by the X gene.