title: The bovine leukemia virus tax gene contains an enhancer sequence.
abstract: Transactivator proteins of the bovine leukemia (BLV) and human T-lymphotropic (HTLV) viruses increase long terminal repeat (LTR)-directed viral gene expression and act as immortalizing oncogenes in tissue culture. We report here that the BLV tax gene sequence contains an enhancer-like activity. The X long open reading frame was cloned up-stream of the beta-globin promoter linked to the chloramphenicol acetyltransferase (CAT) gene. In the presence of tax sequences, up to sevenfold enhancement of CAT expression was observed. A computer-assisted homology search revealed the presence of a consensus enhancer core sequence (GTGTTGTTGGTTG) into the third exon of the 2.1-kb X mRNA. These studies demonstrate that the tax gene contains a transcriptional enhancer which could be involved in early viral gene expression in vivo.
authors.affiliation: Department of Molecular Biology, Faculty of Agronomy, Gembloux, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Willems
authors.forename: P C
authors.initials: PC
authors.lastname: Romond
authors.forename: J
authors.initials: J
authors.lastname: Ghysdael
authors.forename: A
authors.initials: A
authors.lastname: Burny
authors.forename: R
authors.initials: R
authors.lastname: Kettmann
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004279:DNA, Viral / Q000235:genetics; D004742:Enhancer Elements, Genetic; D015967:Gene Expression Regulation, Viral; D016356:Gene Products, tax / Q000235:genetics*; D006801:Humans; D001909:Leukemia Virus, Bovine / Q000235:genetics*; D008969:Molecular Sequence Data; D013329:Structure-Activity Relationship
chemical_list: D004279:DNA, Viral; D016356:Gene Products, tax