NusA protein is necessary and sufficient in vitro for phage lambda N gene product to suppress a rho-independent terminator placed downstream of nutL.
Transcription antitermination by phage lambda N protein is reproduced in vitro solely with purified components. We have placed a strong rho-independent terminator, lambda tR', in the PL operon about 200 base pairs downstream from the N-recognition site, nutL, and have monitored terminated and run-off transcripts produced by single-round transcription of linear plasmids. In the presence of NusA, one of several host factors implicated in antitermination, N is found to virtually abolish termination at tR'. N is unable to suppress termination if the terminator is preceded by a defective nut site. Thus, during transcription through the nut site, N and NusA can modify RNA polymerase to a termination-resistant form in the absence of any other accessory factor.
Whalen
W
W
Department of Microbiology, University of Connecticut, Farmington 06032.
Ghosh
B
B
Das
A
A
D001426:Bacterial Proteins / Q000502:physiology*; D010582:Bacteriophage lambda / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D012234:Rho Factor / Q000502:physiology*; D013728:Terminator Regions, Genetic; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000502:physiology*
D001426:Bacterial Proteins; D012234:Rho Factor; D014157:Transcription Factors; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases