title: Modulation of expression of the hepatitis B virus surface antigen gene by the viral X-gene product.
abstract: Human hepatoma cells (HepG2 and HUH7) transfected with a plasmid (pHBV1004) containing the transcription units for the major surface antigen (S) mRNA and the X mRNA of hepatitis B virus (HBV) secreted surface antigen (HBsAg) into the culture medium. A frameshift mutation in the X gene carried by pHBV1004 greatly reduced HBsAg production by cells transfected with an equivalent amount of the mutant (pHBV1004-B). The mutation could be complemented by cotransfection with a plasmid (pSV2HBX) containing the X structural gene under control of the SV40 early promoter. HBsAg production by cells cotransfected with pHBV1004-B and pSV2HBX was equivalent to that in cells transfected with the parent plasmid (pHBV1004) alone. Levels of HBsAg production were directly related to the amount of S mRNA produced, showing that the X-gene product (HBxAg) can modulate expression of the S gene.
authors.affiliation: Department of Molecular Biology, University of Edinburgh, Scotland, U.K.
authors.forename: M T
authors.initials: MT
authors.lastname: Rossner
authors.forename: R J
authors.initials: RJ
authors.lastname: Jackson
authors.forename: K
authors.initials: K
authors.lastname: Murray
mesh_terms: D015870:Gene Expression; D005814:Genes, Viral; D005816:Genetic Complementation Test; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics* / Q000276:immunology; D006801:Humans; D009154:Mutation; D010957:Plasmids; D012333:RNA, Messenger / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D006514:Hepatitis B Surface Antigens; D012333:RNA, Messenger; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein