Identification and characterization of the gene products of open reading frame U86/87 of human herpesvirus 6

Virus Res. 2002 Oct;89(1):89-101. doi: 10.1016/s0168-1702(02)00126-0.


The human herpesvirus 6 (HHV-6) immediate early-A locus (IE-A) locates in the position analogous to the human cytomegalovirus (HCMV) major IE (MIE) locus that is well-known to play critical roles in viral infection. Similarly to HCMV MIE, HHV-6 IE-A consists of two genetic units, IE1 and IE2, corresponding to open reading frames U90-U89 and U90-U86/87, respectively. However, the HHV-6 IE-A locus exhibits limited sequence homology with the HCMV MIE locus. In this study, to characterize HHV-6 IE2 gene products, polyclonal antibodies against four domains of the U86/87 open reading frame were generated by immunization of rabbits with bacterially-expressed proteins. Three polypeptides derived from the U86/87 region with apparent molecular masses of 100, 85 and 55 kD were detected in HHV-6-infected cells 3 days after infection, while IE1 polypeptides with apparent molecular mass greater than 170 kD were detectable as early as 8 h. Mapping of the IE2 gene products with the antibodies suggests differential splicing and alternative translation initiation in the IE2 genetic unit. The IE2 products show a mixed cytoplasmic and nuclear localization pattern. In addition, the 437 amino acid carboxyl-terminus domain bound to a DNA fragment containing the putative IE-A promoter. These results suggest that HHV-6 IE2 plays a critical role in transcriptional regulation and viral growth as does HCMV IE2, although it is likely that HHV-6 IE2 has expression kinetics different from HCMV IE2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Viral / blood
  • Antibodies, Viral / immunology
  • Cells, Cultured
  • DNA-Binding Proteins / metabolism
  • Fetal Blood / cytology
  • Gene Expression Regulation, Viral*
  • Herpesvirus 6, Human / genetics
  • Herpesvirus 6, Human / growth & development
  • Herpesvirus 6, Human / metabolism*
  • Humans
  • Immediate-Early Proteins* / chemistry
  • Immediate-Early Proteins* / genetics
  • Immediate-Early Proteins* / immunology
  • Immediate-Early Proteins* / metabolism
  • Immunization
  • Immunoblotting
  • Lymphocytes / virology
  • Open Reading Frames / genetics*
  • Rabbits
  • Recombinant Fusion Proteins / immunology
  • Transcription, Genetic
  • Viral Proteins / chemistry
  • Viral Proteins / genetics
  • Viral Proteins / immunology
  • Viral Proteins / metabolism


  • Antibodies, Viral
  • DNA-Binding Proteins
  • Immediate-Early Proteins
  • Recombinant Fusion Proteins
  • Viral Proteins