title: Functional organization of the hepatitis B virus enhancer.
abstract: We have studied the functional constituents of the hepatitis B virus enhancer in a number of cell lines. The sequence of this enhancer, being embedded within an open reading frame of the virus, is in part evolutionarily frozen and therefore serves as a good model to investigate the fundamental enhancer elements. The hepatitis B virus enhancer contains three functionally important DNA sequence elements, EP, E, and NF-1a, each of which is bound by a distinct protein(s). The synergistic action of these elements accounts for all of the enhancer activity in a nonliver cell line and for most, but not all, of the activity in liver-derived cell lines. Multimers of the E but not of the EP element act as an autonomous enhancer. Conversely, a single element of either the E or the NF-1a element can act only when linked to the EP element. These results suggest that EP is a crucial enhancer element that acts only in interaction with a second enhancer element with intrinsic enhancer activity. Interestingly, a highly similar enhancer structure is found in a number of distinct viruses.
authors.affiliation: Department of Molecular Genetics and Virology, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Dikstein
authors.forename: O
authors.initials: O
authors.lastname: Faktor
authors.forename: R
authors.initials: R
authors.lastname: Ben-Levy
authors.forename: Y
authors.initials: Y
authors.lastname: Shaul
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004279:DNA, Viral / Q000235:genetics; D003850:Deoxyribonuclease I; D004742:Enhancer Elements, Genetic; D006515:Hepatitis B virus / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D015345:Oligonucleotide Probes; D010957:Plasmids; D011485:Protein Binding; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D004279:DNA, Viral; D009687:Nuclear Proteins; D015345:Oligonucleotide Probes; D003850:Deoxyribonuclease I