Assembly of transcription elongation complexes containing the N protein of phage lambda and the Escherichia coli elongation factors NusA, NusB, NusG, and S10.
The transcription antitermination protein, N, of bacteriophage lambda; the Escherichia coli elongation factors NusA, NusB, ribosomal protein S10, and NusG; and a DNA template containing a lambda nut (N-ututilization) site are necessary and sufficient for the highly cooperative formation in vitro of stable transcription complexes containing all five elongation factors. Mutations in the nut site, NusA, or the beta-subunit of RNA polymerase (RNAP) that impair antitermination in vivo also abolish the assembly of a stable complex containing the antitermination factors in vitro. The effects of RNAP mutations on assembly imply that the antitermination factors assemble on the surface of RNAP. We have shown previously that NusA binds directly to transcribing RNAP (Ka approximately 10(7) M-1); Ka = association constant and we show here that S10 also binds directly and specifically to RNAP with an apparent Ka of 10(6) M-1. These observations led to a model for the ordered assembly of the N-modified transcription complex.
Mason
S W
SW
Department of Medical and Molecular Genetics, University of Toronto, Canada.
Greenblatt
J
J
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D010582:Bacteriophage lambda / Q000235:genetics*; D002850:Chromatography, Gel; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D008957:Models, Genetic; D010445:Peptide Elongation Factors / Q000235:genetics / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; C074952:NusB protein, E coli; C070291:NusG protein, E coli; D010445:Peptide Elongation Factors; D012269:Ribosomal Proteins; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D014764:Viral Proteins; C068727:nusA protein, E coli; C029537:ribosomal protein S10; D012321:DNA-Directed RNA Polymerases