title: Differences in the target specificity of the transactivating factors MHBs(t) and HBx of hepatitis B virus.
abstract: Transient transfections of tissue culture cells with plasmids encoding the transactivating factors MHBs(t) and HBx of hepatitis B virus result in transcriptional stimulation of multiple target genes. Our experiments show that the NF-kappaB-binding enhancer element of simian virus 40 (SV40) and the AP-1-binding enhancer element of the human metallothionein IIA gene mediate the transactivating function of MHBs(t) and HBx. In contrast, the elements GT(IIC + I) and Sph(II + I) of the SV40 enhancer, that, as a common feature, require binding of transcription factor TEF-1 for activity, efficiently mediate transactivation only by HBx but not by MHBs(t). This finding suggests that at least one regulatory pathway exists that can only be activated by HBx but not by MHBs(t).
authors.affiliation: Max-Planck-Institut für Biochemie, Department of Virus Research, Martinsried, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Mühlbauer
authors.forename: W
authors.initials: W
authors.lastname: Koch
mesh_terms: D002460:Cell Line; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D008668:Metallothionein / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D013539:Simian virus 40 / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D006514:Hepatitis B Surface Antigens; D016328:NF-kappa B; D015534:Trans-Activators; D018808:Transcription Factor AP-1; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D008668:Metallothionein