title: Human herpesvirus 6 major immediate early promoter has strong activity in T cells and is useful for heterologous gene expression.
abstract: BACKGROUND
  Human herpesvirus-6 (HHV-6) is a beta-herpesvirus. HHV-6 infects and replicates in T cells. The HHV-6-encoded major immediate early gene (MIE) is expressed at the immediate-early infection phase. Human cytomegalovirus major immediate early promoter (CMV MIEp) is commercially available for the expression of various heterologous genes. Here we identified the HHV-6 MIE promoter (MIEp) and compared its activity with that of CMV MIEp in various cell lines.
  
  
  METHODS
  The HHV-6 MIEp and some HHV-6 MIEp variants were amplified by PCR from HHV-6B strain HST. These fragments and CMV MIEp were subcloned into the pGL-3 luciferase reporter plasmid and subjected to luciferase reporter assay. In addition, to investigate whether the HHV-6 MIEp could be used as the promoter for expression of foreign genes in a recombinant varicella-zoster virus, we inserted HHV-6 MIEp-DsRed expression casette into the varicella-zoster virus genome.
  
  
  RESULTS
  HHV-6 MIEp showed strong activity in T cells compared with CMV MIEp, and the presence of intron 1 of the MIE gene increased its activity. The NF-κB-binding site, which lies within the R3 repeat, was critical for this activity. Moreover, the HHV-6 MIEp drove heterologous gene expression in recombinant varicella-zoster virus-infected cells.
  
  
  CONCLUSIONS
  These data suggest that HHV-6 MIEp functions more strongly than CMV MIEp in various T-cell lines.
authors.affiliation: Laboratoy of Virology, Division of Biomedical Research, National Institute of Biomedical Innovation, 7-6-8, Saito-Asagi, Ibaraki, Osaka 567-0085, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Matsuura
authors.forename: Masaya
authors.initials: M
authors.lastname: Takemoto
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamanishi
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Mori
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D003587:Cytomegalovirus / Q000235:genetics; D015870:Gene Expression / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D017781:Genes, Immediate-Early / Q000235:genetics*; D005821:Genetic Techniques; D014645:Herpesvirus 3, Human / Q000235:genetics; D015654:Herpesvirus 6, Human / Q000235:genetics*; D006801:Humans; D019169:Jurkat Cells; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011995:Recombination, Genetic / Q000235:genetics; D013601:T-Lymphocytes / Q000378:metabolism* / Q000821:virology