The Herpesvirus saimiri replication and transcription activator acts synergistically with CCAAT enhancer binding protein alpha to activate the DNA polymerase promoter. Academic Article uri icon

Overview

MeSH

  • Binding Sites
  • Cell Line
  • Codon, Initiator
  • Humans
  • Promoter Regions, Genetic
  • Protein Binding
  • Response Elements
  • Virus Activation

MeSH Major

  • CCAAT-Enhancer-Binding Protein-alpha
  • DNA-Directed DNA Polymerase
  • Herpesvirus 2, Saimiriine
  • Immediate-Early Proteins
  • Trans-Activators
  • Transcriptional Activation
  • Viral Proteins

abstract

  • The open reading frame (ORF) 50 gene product, also known as the replication and transcription activator (Rta), is an immediate-early gene which is well conserved among all gamma-2 herpesviruses and plays a pivotal role in regulating the latent-lytic switch. Herpesvirus saimiri (HVS) ORF 50a functions as a sequence-specific transactivator capable of activating delayed-early (DE) gene expression via binding directly to an ORF 50 response element (RE) within the respective promoter. Analysis of the ORF 50 REs have identified two distinct types within HVS gene promoters. The first comprises a consensus sequence motif, CCN(9)GG, the second an AT-rich sequence. Here we demonstrate that ORF 50a is capable of transactivating the DE ORF 9 promoter which encodes the DNA polymerase. Deletion analysis of the ORF 9 promoter mapped the ORF 50 RE to a 95-bp region situated 126 bp upstream of the initiation codon. Gel retardation analysis further mapped the RE to a 28-bp fragment, which was able to confer ORF 50 responsiveness on an enhancerless simian virus 40 minimal promoter. Furthermore, sequence analysis identified multiple CCAAT enhancer binding protein alpha (C/EBPalpha) binding sites within the ORF 9 promoter and specifically two within the close vicinity of the AT-rich ORF 50 RE. Analysis demonstrated that the HVS ORF 50a and C/EBPalpha proteins associate with the ORF 9 promoter in vivo, interact directly, and synergistically activate the ORF 9 promoter by binding to adjacent binding motifs. Overall, these data suggest a cooperative interaction between HVS ORF 50a and C/EBPalpha proteins to activate the DNA polymerase promoter during early stages of the lytic replication cycle.

publication date

  • November 2005

has subject area

  • Binding Sites
  • CCAAT-Enhancer-Binding Protein-alpha
  • Cell Line
  • Codon, Initiator
  • DNA-Directed DNA Polymerase
  • Herpesvirus 2, Saimiriine
  • Humans
  • Immediate-Early Proteins
  • Promoter Regions, Genetic
  • Protein Binding
  • Response Elements
  • Trans-Activators
  • Transcriptional Activation
  • Viral Proteins
  • Virus Activation

Research

keywords

  • Journal Article

Identity

Language

  • eng

PubMed Central ID

  • PMC1262591

Digital Object Identifier (DOI)

  • 10.1128/JVI.79.21.13548-13560.2005

PubMed ID

  • 16227275

Additional Document Info

start page

  • 13548

end page

  • 13560

volume

  • 79

number

  • 21