Inactivation of the very strong HCMV immediate early promoter by DNA CpG methylation in vitro

Biol Chem Hoppe Seyler. 1996 Mar;377(3):195-201. doi: 10.1515/bchm3.1996.377.3.195.


The influence of DNA methylation in vitro on the activity of the very strong human cytomegalovirus (HCMV) major immediate early (IE) modulator/enhancer/promoter region was investigated by transient transfection experiments of premonocytic HL-60 cells. While sequence-specific methylation of the major IE enhancer and/or modulator with the cytosine methyl-transferases FnuDII, HhaI and HaeIII had no significant effect, the promoter activity was completely repressed by methylation of the cytosine in 5'-CpG sites with the Spiroplasma methyltransferase SssI. Addition of TNF-alpha or PMA which are strong stimulators of HCMV major IE enhancer/promoter activity in premonocytic HL-60 cells had no effect on repression. Inactivation of the IE enhancer/promoter via methylation by M.SssI could be partially alleviated by co-transfection with an excess of untranscribable highly methylated DNA. These results indicate that a methyl-CpG binding factor is involved as mediator in the inhibitory effect of HCMV enhancer/promoter methylation. Taken together, the HCMV major IE enhancer/ promoter has been shown to be susceptible to transcriptional inactivation by methylation of the cytosines in CpG dinucleotides, a process that is proposed to play a modulatory role in viral latency.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Viral / genetics*
  • Base Sequence
  • Binding, Competitive
  • Cytomegalovirus / genetics*
  • DNA / metabolism
  • DNA-Cytosine Methylases / metabolism*
  • Dinucleoside Phosphates / metabolism*
  • Enhancer Elements, Genetic
  • Gene Expression Regulation, Viral
  • HL-60 Cells
  • Humans
  • Immediate-Early Proteins / genetics*
  • Methylation
  • Molecular Sequence Data
  • Promoter Regions, Genetic*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Tumor Necrosis Factor-alpha / pharmacology


  • Antigens, Viral
  • Dinucleoside Phosphates
  • Immediate-Early Proteins
  • Tumor Necrosis Factor-alpha
  • immediate-early proteins, cytomegalovirus
  • cytidylyl-3'-5'-guanosine
  • DNA
  • DNA modification methylase SssI
  • DNA-Cytosine Methylases
  • Tetradecanoylphorbol Acetate