Escherichia coli nusG mutations that block transcription termination by coliphage HK022 Nun protein.
The Escherichia coli nusG gene product is required for transcription termination by phage HK022 Nun protein at the lambda nutR site in vivo. We show that it is also essential for Nun termination at lambda nutL. Three recessive mis-sense nusG mutations have been isolated that inhibit termination by Nun at lambda nutR. The mutations are ineffective in a lambda pL nutL fusion, even when lambda nutR replaces lambda nutL. The mutant strains support lambda growth, indicating that lambda N antitermination activity is not impaired. Transcription arrest by Nun in vitro is stimulated by NusG protein at both lambda nutR and lambda nutL. Mutant NusG protein fails to enhance transcriptional arrest by Nun at either site. The mutant protein, like the wild-type protein, suppresses transcriptional pausing by RNA polymerase and stimulates Rho-dependent termination. These results imply that the role of NusG in Nun termination may be distinct from its roles in other transcription reactions.
Burova
E
E
Institute of Cancer Research, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
Hung
S C
SC
Chen
J
J
Court
D L
DL
Zhou
J G
JG
Mogilnitskiy
G
G
Gottesman
M E
ME
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division; D003090:Coliphages / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D008957:Models, Genetic; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010445:Peptide Elongation Factors / Q000235:genetics*; D010957:Plasmids; D012234:Rho Factor / Q000502:physiology; D012269:Ribosomal Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; 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; C073501:Nun protein, Enterobacteria phage HK022; C074952:NusB protein, E coli; C070291:NusG protein, E coli; C119762:NutR protein, bacteriophage lambda; D010445:Peptide Elongation Factors; D012234:Rho Factor; D012269:Ribosomal Proteins; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D014764:Viral Proteins; C068727:nusA protein, E coli; C029537:ribosomal protein S10