Enhancer binding factors AP-4 and AP-1 act in concert to activate SV40 late transcription in vitro

Nature. 1988 Apr 7;332(6164):557-61. doi: 10.1038/332557a0.

Abstract

The simian virus 40 (SV40) transcriptional enhancer is composed of multiple cis-acting DNA sequence motifs, each individually having a two- to fourfold effect on the efficiency of transcription. When various distinct cis-elements act in combination, however, a dramatic enhancement of transcription initiation often results. SV40-enhancer A-domain sequences were previously shown to be important for early and late transcription in vivo. Here we report the isolation of the enhancer binding factor AP-4, which recognizes a motif in this domain. Purified AP-4 activates SV40 late transcription in vitro, and this stimulation is augmented by the addition of transcription factor AP-1 which binds to adjacent sequences in the A-domain, suggesting coordinate action of the two factors for transcriptional enhancement. AP-1 also represses late transcription from a major in vitro start site which is poorly used in vivo, indicating that AP-1 can act as both a positive and negative regulator of SV40 late transcription. Thus by manipulating the levels of different trans-acting factors in vitro, we can recreate the pattern of SV40 late initiation observed during the viral lytic cycle in vivo.

Publication types

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

MeSH terms

  • Base Sequence
  • DNA-Binding Proteins / physiology*
  • Enhancer Elements, Genetic*
  • Genes, Viral*
  • HeLa Cells / metabolism
  • Humans
  • Molecular Sequence Data
  • Proto-Oncogene Proteins c-jun
  • Simian virus 40 / genetics*
  • Transcription Factors / physiology*
  • Transcription, Genetic*

Substances

  • DNA-Binding Proteins
  • Proto-Oncogene Proteins c-jun
  • Transcription Factors
  • enhancer-binding protein AP-4