NusA is required for ribosomal antitermination and for modulation of the transcription elongation rate of both antiterminated RNA and mRNA.
Ribosomal RNA (rRNA) is elongated twice as fast as mRNA in vivo due to the presence of antitermination sequences in the 5' part of the rRNA transcripts. A number of Nus factors bind to RNA polymerase at the antitermination sites and help confer resistance to Rho-dependent termination of transcription. In this paper, the effects of the nusAcs10 allele on the elongation rate of both mRNA and antiterminated RNA were investigated. The results indicate that NusA is required to achieve a high elongation rate of RNA chains carrying the ribosomal antitermination boxA and that antitermination is defective when the rate of transcription elongation is decreased by the nusAcs10 allele. Furthermore, the nusAcs10 allele had no significant effects on the elongation rate of normal lacZ mRNA during steady state growth, but it abolished the inhibition of lacZ mRNA elongation by guanosine 3',5'-bis(diphosphate) (ppGpp). These results suggest that NusA is the component of the transcription elongation complex required for inhibition of mRNA elongation by ppGpp.
Vogel
U
U
Department of Biological Chemistry, Institute of Molecular Biology, University of Copenhagen, Solvgade 83H, DK-1307 Copenhagen K, Denmark.
Jensen
K F
KF
D000483:Alleles; D001426:Bacterial Proteins / Q000378:metabolism*; D029968:Escherichia coli Proteins; D007763:Lac Operon / Q000235:genetics; D009690:Nucleic Acid Conformation; D010445:Peptide Elongation Factors; D012333:RNA, Messenger / Q000096:biosynthesis*; D012335:RNA, Ribosomal / Q000096:biosynthesis*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D010445:Peptide Elongation Factors; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; C068727:nusA protein, E coli