Broad specificity of the hepatitis B enhancer function.

The genome of hepatitis B virus (HBV) contains an enhancer element located in the coding region of the DNA polymerase open reading frame between the 3' end of the S gene and the X gene. To determine whether HBV enhancer is species and/or tissue specific, several cell lines were transfected with CAT plasmids containing different subgenomic fragments of the HBV genome. The activity of the HBV transcriptional enhancer sequence was shown not to be strictly hepatotropic, since it was found in hematopoietic tissues. This activity was not species specific either, since it was found in feline and mouse cells.