Modulation of human cytomegalovirus immediate-early gene enhancer by mitogen-activated protein kinase kinase kinase-1

J Cell Biochem. 2001;83(4):563-73. doi: 10.1002/jcb.1251.

Abstract

The immediate-early (IE) promoter of human cytomegalovirus (HCMV) constitutes a primary genetic switch, which determines the progression of viral infection. Earlier reports by others have shown mitogen-activated protein kinase kinase kinase-1 (MEKK1) to be able to up-regulate HCMV-IE promoter through downstream mitogen-activated protein kinase (MAPK) pathways. However, we noticed that the activation of the HCMV-IE promoter by constitutively active MEKK1 (MEKK1-TRU) might not be through the MAPK pathways. Using a HCMV-IE enhancer/promoter (- 522 to + 72) driving a luciferase reporter, we demonstrated that the downstream MAPK activation actually repressed the up-regulation of the promoter by MEKK1 in CHO-K1 and human 293 cells. We further found that the up-regulation of HCMV-IE promoter by MEKK1 could be in great extent suppressed by over-expression of IkappaBalpha. Deletion of the NFkappaB/rel sites in the HCMV-IE enhancer region by mutagenesis proportionally reduced the transcriptional activation by MEKK1-TRU, whereas deletion of the ATF/CREB binding sites or cyclic AMP response elements (CRE) had no effects. Furthermore, the NFkappaB/rel deletion mutant also showed repression on the basic transcription activity of the HCMV-IE promoter. Our results indicate that the NFkappaB/rel sites are not only responsible for the modulation of HCMV-IE enhancer activity by MEKK1 but also control the basic transcription activity of the HCMV-IE promoter. On the other hand, the four consensus CRE sites were found to have no function in the activation of the promoter by MEKK1.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Binding Sites / genetics
  • CHO Cells
  • Cell Line
  • Cricetinae
  • Cyclic AMP Response Element-Binding Protein / genetics
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Cytomegalovirus / genetics*
  • Enhancer Elements, Genetic*
  • Gene Deletion
  • Genes, Immediate-Early*
  • Genetic Vectors / pharmacology
  • Humans
  • I-kappa B Kinase
  • Immediate-Early Proteins
  • Isoenzymes / biosynthesis
  • JNK Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinase 1*
  • Membrane Glycoproteins*
  • Mitogen-Activated Protein Kinases / biosynthesis
  • Mitogen-Activated Protein Kinases / physiology
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Promoter Regions, Genetic
  • Protein Serine-Threonine Kinases / physiology*
  • Rats
  • Repressor Proteins / physiology
  • Trans-Activators*
  • Transcriptional Activation
  • Up-Regulation / genetics
  • Viral Envelope Proteins*
  • Viral Proteins*
  • p38 Mitogen-Activated Protein Kinases

Substances

  • Cyclic AMP Response Element-Binding Protein
  • IE1 protein, cytomegalovirus
  • IE2 protein, Cytomegalovirus
  • Immediate-Early Proteins
  • Isoenzymes
  • Membrane Glycoproteins
  • NF-kappa B
  • Repressor Proteins
  • Trans-Activators
  • UL115 protein, Human herpesvirus 5
  • Viral Envelope Proteins
  • Viral Proteins
  • glycoprotein H, Cytomegalovirus
  • glycoprotein H, Human cytomegalovirus
  • glycoprotein O, cytomegalovirus
  • Protein Serine-Threonine Kinases
  • CHUK protein, human
  • I-kappa B Kinase
  • IKBKB protein, human
  • IKBKE protein, human
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • p38 Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinase 1
  • MAP3K1 protein, human