The sigma(70) subunit of RNA polymerase is contacted by the (lambda)Q antiterminator during early elongation.
The Q protein of bacteriophage lambda is a transcription antiterminator that modifies the elongation properties of E. coli RNA polymerase (RNAP). To do this, DNA-bound (lambda)Q must first engage a paused elongation complex. Here we show that this engagement of (lambda)Q with RNAP involves an interaction between (lambda)Q and sigma(70), demonstrating that sigma(70) can be a target of regulation during elongation. Furthermore, we provide evidence that this interaction between (lambda)Q and sigma(70) stabilizes a conformation of RNAP that requires the disengagement of a segment of sigma(70) from the core enzyme. Recent structure-based models posit that the transition from the initiation to the elongation phase of transcription involves the staged displacement of sigma(70) from the RNAP core. Our findings provide support for this proposal.
Nickels
Bryce E
BE
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
Roberts
Christine W
CW
Sun
Haitao
H
Roberts
Jeffrey W
JW
Hochschild
Ann
A
D010582:Bacteriophage lambda / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D008957:Models, Genetic; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D004268:DNA-Binding Proteins; C066119:Q protein, Bacteriophage lambda; D011993:Recombinant Fusion Proteins; D012808:Sigma Factor; D014764:Viral Proteins; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases