The IE2 gene products of human cytomegalovirus specifically down-regulate expression from the major immediate-early promoter through a target sequence located near the cap site

M. C. Pizzorno, G. S. Hayward

Research output: Contribution to journalArticlepeer-review

Abstract

The 82-kDa IE2 protein of human cytomegalovirus (HCMV) acts as both a powerful nonspecific trans activator of heterologous promoters and a negative autoregulator of HCMV immediate-early gene expression in transient assays. We show here that the highly specific down-regulation effect occurs in permissive diploid human fibroblast cells as well as in nonpermissive Vero cells and that the target sequences are conserved within the major immediate-early promoters of both HCMV and simian cytomegalovirus. The response sequences were localized between -67 and +30 in the simian cytomegalovirus IE94 promoter and upstream of position +9 in the HCMV IE68 promoter. Deletion of sequences downstream of -14 in a target IE68-CAT gene abolished the negative phenotype and resulted in a reporter gene that was stimulated instead of inhibited by cotransfection with IE2 effector DNA. Insertion of an oligonucleotide containing sequences from between -17 and +9 into the IE68-CAT deletion construction restored autoregulation in either orientation. Furthermore, this same oligonucleotide transferred the full down-regulation phenotype when inserted at +10 into the nonresponsive IE175 promoter from herpes simplex virus. Therefore, a specific response signal that acts at the DNA level must lie within these boundaries. Additional analysis with inserted oligonucleotides containing deletions or point mutations revealed that essential components of the signal lie between positions -12 and +5. Therefore, negative autoregulation by HCMV IE2 in DNA contransfection systems resembles that for simian virus 40 large T antigen and herpes simplex virus IE175 by acting through a signal located near the cap site, but the target sequence itself bears no resemblance to those utilized in these other viral systems.

Original languageEnglish (US)
Pages (from-to)6154-6165
Number of pages12
JournalJournal of virology
Volume64
Issue number12
DOIs
StatePublished - 1990

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

Fingerprint Dive into the research topics of 'The IE2 gene products of human cytomegalovirus specifically down-regulate expression from the major immediate-early promoter through a target sequence located near the cap site'. Together they form a unique fingerprint.

Cite this