Resumen de Functional Interaction between RNA Polymerase α Subunit C-Terminal Domain and σ70 in UP-Element- and Activator-Dependent Transcription

Hong Tang, Hao Chen, Richard H. Ebright

• We show that the Escherichia coli RNA polymerase (RNAP) α subunit C-terminal domain (αCTD) functionally interacts with σ70 at a subset of UP-element- and activator-dependent promoters, we define the determinants of αCTD and σ70 required for the interaction, and we present a structural model for the interaction. The αCTD-σ70 interaction spans the upstream promoter and core promoter, thereby linking recognition of UP-elements and activators in the upstream promoter with recognition of the −35 element in the core promoter. We propose that the αCTD-σ70 interaction permits UP-elements and activators not only to “recruit” RNAP through direct interaction with αCTD, but also to “remodel” RNAP-core-promoter interaction through indirect, αCTD-bridged interactions with σ70.