A regulatory protein that interferes with activator-stimulated transcription in bacteria

Shunji Nakano, Michiko M. Nakano, Ying Zhang, Montira Leelakriangsak, Peter Zuber

Research output: Contribution to journalArticlepeer-review

118 Scopus citations


Transcriptional activator proteins in bacteria often operate by interaction with the C-terminal domain of the α-subunit of RNA polymerase (RNAP). Here we report the discovery of an "anti-α" factor Spx in Bacillus subtilis that blocks transcriptional activation by binding to the α-C-terminal domain, thereby interfering with the capacity of RNAP to respond to certain activator proteins. Spx disrupts complex formation between the activator proteins ResD and ComA and promoter-bound RNAP, and it does so by direct interaction with the α-subunit. ResD- and ComA-stimulated transcription requires the proteolytic elimination of Spx by the ATP-dependent protease CIpXP. Spx represents a class of transcriptional regulators that inhibit activator-stimulated transcription by interaction with α.

Original languageEnglish (US)
Pages (from-to)4233-4238
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number7
StatePublished - Apr 1 2003
Externally publishedYes


  • Bacillus subtilis
  • RNA polymerase
  • Spx
  • Transcriptional activation
  • α-subunit

ASJC Scopus subject areas

  • General


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