PMID:12853450

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Citation

Lacour, S, Kolb, A and Landini, P (2003) Nucleotides from -16 to -12 determine specific promoter recognition by bacterial sigmaS-RNA polymerase. J. Biol. Chem. 278:37160-8

Abstract

The alternative sigma factor sigmaS, mainly active in stationary phase of growth, recognizes in vitro a -10 promoter sequence almost identical to the one for the main sigma factor, sigma70, thus raising the problem of how specific promoter recognition by sigmaS-RNA polymerase (EsigmaS) is achieved in vivo. We investigated the promoter features involved in selective recognition by EsigmaS at the strictly sigmaS-dependent aidB promoter. We show that the presence of a C nucleotide as first residue of the aidB -10 sequence (-12C), instead of the T nucleotide canonical for sigma70-dependent promoters, is the major determinant for selective recognition by EsigmaS. The presence of the -12C does not allow formation of an open complex fully proficient in transcription initiation by Esigma70. The role of -12C as specific determinant for promoter recognition by EsigmaS was confirmed by sequence analysis of known EsigmaS-dependent promoters as well as site-directed mutagenesis at the promoters of the csgB and sprE genes. We propose that EsigmaS, unlike Esigma70, can recognize both C and T as the first nucleotide in the -10 sequence. Additional promoter features such as the presence of a C nucleotide at position -13, contributing to open complex formation by EsigmaS, and a TG motif found at the unusual -16/-15 location, possibly contributing to initial binding to the promoter, also represent important factors for sigmaS-dependent transcription. We propose a new sequence, TG(N)0-2CCATA(c/a)T, as consensus -10 sequence for promoters exclusively recognized by EsigmaS.

Links

PubMed Online version:10.1074/jbc.M305281200

Keywords

Bacterial Proteins/metabolism; Base Sequence; DNA-Directed RNA Polymerases/metabolism; Escherichia coli Proteins/metabolism; Molecular Sequence Data; Potassium Permanganate/pharmacology; Promoter Regions, Genetic; Sigma Factor/metabolism; Transcription, Genetic

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