title: Activation of the HTLV-I long terminal repeat by the hepatitis B virus X protein.
abstract: The human T-cell leukemia virus type I (HTLV-I) Tax protein and the hepatitis B virus (HBV) X protein have each been shown to activate transcription of their respective viral promoters as well as a subset of cellular gene promoters. Here we show that the HTLV-I long terminal repeat (LTR) is responsive to HBV X transactivation. Maximum levels of X-mediated transactivation of the LTR were 8-fold. An X-responsive-region (XRR) of the LTR is located between nucleotides -355 and -276 and contains an AP-2 binding site, a previously recognized X-responsive element. We demonstrated that Tax and X synergize to activate transcription from the HTLV-I LTR, although the AP-2 binding site was not required for this synergy. These results raise the possibility that the HBV X protein may affect the level of HTLV-I gene expression in co-infected individuals.
authors.affiliation: Division of Molecular Virology, Baylor College of Medicine, Houston, Texas 77030, USA. susanm@bcm.tmc.edu
authors.forename: S J
authors.initials: SJ
authors.lastname: Marriott
authors.forename: T H
authors.initials: TH
authors.lastname: Lee
authors.forename: B L
authors.initials: BL
authors.lastname: Slagle
authors.forename: J S
authors.initials: JS
authors.lastname: Butel
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D004279:DNA, Viral; D004268:DNA-Binding Proteins / Q000235:genetics; D016356:Gene Products, tax / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006515:Hepatitis B virus / Q000235:genetics / Q000502:physiology*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000235:genetics; D015533:Transcriptional Activation; D054334:Viral Regulatory and Accessory Proteins
chemical_list: D004279:DNA, Viral; D004268:DNA-Binding Proteins; D016356:Gene Products, tax; D015534:Trans-Activators; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein