Oligomerization of NTRC at the glnA enhancer is required for transcriptional activation

Susan C. Porter, Anne K. North, Andrew B. Wedel, Sydney Kustu

Research output: Contribution to journalArticlepeer-review

156 Scopus citations


To activate transcription of the glnA gene, the dimeric NTRC protein (nitrogen regulatory protein C) of enteric bacteria binds to an enhancer located ∼100 bp upstream of the promoter. The enhancer is composed of two binding sites for NTRC that are three turns of the DNA helix apart. One role of the enhancer is to tether NTRC in high local concentration near the promoter to allow for its frequent interaction with σ54 holoenzyme by DNA looping. We have found that a second role of the enhancer is to ensure oligomerization of NTRC into a complex of at least two dimers that is required for transcriptional activation. Formation of this complex is greatly facilitated by a protein-protein interaction between NTRC dimers that is increased when the protein is phosphorylated.

Original languageEnglish (US)
Pages (from-to)2258-2273
Number of pages16
JournalGenes and Development
Issue number11
StatePublished - 1993


  • Cooperativity
  • Enhancer
  • NTRA
  • NTRC
  • Oligomerization
  • Transcriptional regulation

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology


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