Region 1.2 of the RNA polymerase sigma subunit controls recognition of the -10 promoter element.

Nikolay Zenkin , Andrey Kulbachinskiy , Yuliya Yuzenkova , Arkady Mustaev , Irina Bass , Konstantin Severinov , Konstantin Brodolin (1)

1 IRIM - Institut de Recherche en Infectiologie de Montpellier

Recognition of the -10 promoter consensus element by region 2 of the bacterial RNA polymerase sigma subunit is a key step in transcription initiation. sigma also functions as an elongation factor, inducing transcription pausing by interacting with transcribed DNA non-template strand sequences that are similar to the -10 element sequence. Here, we show that the region 1.2 of Escherichia coli sigma70, whose function was heretofore unknown, is strictly required for efficient recognition of the non-template strand of -10-like pause-inducing DNA sequence by sigma region 2, and for sigma-dependent promoter-proximal pausing. Recognition of the fork-junction promoter DNA by RNA polymerase holoenzyme also requires sigma region 1.2 and thus resembles the pause-inducing sequence recognition. Our results, together with available structural data, support a model where sigma region 1.2 acts as a core RNA polymerase-dependent allosteric switch that modulates non-template DNA strand recognition by sigma region 2 during transcription initiation and elongation.

Domaines: Bactériologie

Nikolay Zenkin, Andrey Kulbachinskiy, Yuliya Yuzenkova, Arkady Mustaev, Irina Bass, et al.. Region 1.2 of the RNA polymerase sigma subunit controls recognition of the -10 promoter element.. EMBO Journal, 2007, 26 (4), pp.955-64. ⟨10.1038/sj.emboj.7601555⟩. ⟨hal-00346460⟩