Multiple mechanisms are implicated in the regulation of NF-kappa B activity during human cytomegalovirus infection

Proc Natl Acad Sci U S A. 1993 Feb 1;90(3):1107-11. doi: 10.1073/pnas.90.3.1107.


Infection-induced activation of the human cytomegalovirus major immediate early enhancer/promoter has been shown to be regulated primarily by transcription factor NF-kappa B cis elements. However, the mechanism(s) by which human cytomegalovirus induces NF-kappa B activity is unknown. A study was therefore undertaken to determine how this virus would affect normal NF-kappa B regulation. Viral infection of fibroblasts resulted in the specific stimulation of promoters containing major histocompatibility complex NF-kappa B cis elements fused upstream of the chloramphenicol acetyltransferase reporter gene. Electrophoretic mobility shift assays of nuclear extracts derived from mock- and virus-infected cells showed dramatic and sustained increases in DNA-binding proteins specific for these NF-kappa B sequences. Experiments using MAD-3 I kappa B, a specific inhibitor of NF-kappa B, and antibodies directed against rel family members demonstrated that the induced binding activities contained p50 and p65 proteins but not c-rel. Northern analysis indicated maximal levels of p50 mRNA by 4 h postinfection, whereas p65 and MAD-3 I kappa B mRNA accumulation peaked at 48-72 h postinfection, suggesting different regulatory mechanisms for p50 and p65/I kappa B genes. Electrophoretic mobility shift assays with deoxycholate-treated cytoplasmic extracts demonstrated a 3- to 4-fold decrease in the cytosolic stores of NF-kappa B binding activity by 4 h postinfection. Western blots probed with antibodies directed against MAD-3 I kappa B or pp40 (a protein isolated from chicken with sequence and biochemical properties similar to those of MAD-3 I kappa B) indicated that a cross-reactive peptide of 39 kDa was no longer detectable after 24 h postinfection. These results demonstrate that the activation and maintenance of nuclear NF-kappa B DNA binding and enhancer activities upon human cytomegalovirus infection occurs by multiple mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Cell Nucleus / metabolism
  • Cross Reactions
  • Cytomegalovirus Infections / genetics
  • Cytomegalovirus Infections / metabolism*
  • Cytoplasm / metabolism
  • DNA-Binding Proteins / metabolism
  • Enhancer Elements, Genetic*
  • Fibroblasts
  • Humans
  • I-kappa B Proteins*
  • Molecular Sequence Data
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Promoter Regions, Genetic*
  • RNA, Messenger / metabolism
  • Transcriptional Activation*
  • Viral Proteins / immunology


  • DNA-Binding Proteins
  • I-kappa B Proteins
  • NF-kappa B
  • NFKBIA protein, human
  • RNA, Messenger
  • Viral Proteins
  • pp40 protein, Human herpesvirus 5
  • NF-KappaB Inhibitor alpha