The C-terminal domain of the Escherichia coli RNA polymerase   subunit plays a role in the CI-dependent activation of the bacteriophage   pM promoter

Research output: Contribution to journalArticle


  • B Kedzierska
  • A Szambowska
  • A Herman-Antosiewicz
  • G Wegrzyn
  • MS Thomas

Colleges, School and Institutes


The bacteriophage lambda p(M) promoter is required for maintenance of the lambda prophage in Escherichia coli, as it facilitates transcription of the cI gene, encoding the lambda repressor (CI). CI levels are maintained through a transcriptional feedback mechanism whereby CI can serve as an activator or a repressor of p(M). CI activates p(M) through cooperative binding to the O(R)1 and O(R)2 sites within the O(R) operator, with the O(R)2-bound CI dimer making contact with domain 4 of the RNA polymerase sigma subunit (sigma(4)). Here we demonstrate that the 261 and 287 determinants of the C-terminal domain of the RNA polymerase alpha subunit (alphaCTD), as well as the DNA-binding determinant, are important for CI-dependent activation of p(M). We also show that the location of alphaCTD at the p(M) promoter changes in the presence of CI. Thus, in the absence of CI, one alphaCTD is located on the DNA at position -44 relative to the transcription start site, whereas in the presence of CI, alphaCTD is located at position -54, between the CI-binding sites at O(R)1 and O(R)2. These results suggest that contacts between CI and both alphaCTD and sigma are required for efficient CI-dependent activation of p(M).


Original languageEnglish
Pages (from-to)2311-2320
Number of pages10
JournalNucleic Acids Research
Issue number7
Early online date11 Mar 2007
Publication statusPublished - 11 Mar 2007