title: Functional analysis of hepatitis B virus transactivator X: implication of the leucine zipper-like region and C-terminal seven conserved amino acids in functional regions.
abstract: X protein of hepatitis B virus (HBV-X) is a transactivator to a wide variety of viral and cellular transcriptional regulatory elements. Since HBV-X does not act on a common cis-regulatory element of a wide variety of regulatory elements nor does it bind to DNA directly, it has been proposed that HBV-X acts indirectly through protein-protein interactions with other transcription factors or signal transducing pathway. In order to determine the functional domain of HBV-X, we have constructed and analyzed a number of deletion and site specific mutants. Our results showed that leucine zipper-like sequences were found in the C-terminal region of HBV-X and were very important for its transactivating activity. In the analysis of deletion mutants, seven conserved and strong basic amino acids (amino acids 135-141) were essential for the transactivating activity of HBV-X.
authors.affiliation: Molecular Genetics Laboratory, Genetic Engineering Research Institute, Taejon, Korea.
authors.forename: Y H
authors.initials: YH
authors.lastname: Kim
authors.forename: S K
authors.initials: SK
authors.lastname: Kang
authors.forename: Y I
authors.initials: YI
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000378:metabolism; D003001:Cloning, Molecular; D017124:Conserved Sequence; D017931:DNA Primers; D004279:DNA, Viral / Q000378:metabolism; D006511:Hepatitis B Antigens / Q000378:metabolism*; D006515:Hepatitis B virus / Q000378:metabolism*; D006801:Humans; D016350:Leucine Zippers / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010957:Plasmids; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017384:Sequence Deletion; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014407:Tumor Cells, Cultured; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D017931:DNA Primers; D004279:DNA, Viral; D006511:Hepatitis B Antigens; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D015500:Chloramphenicol O-Acetyltransferase