title: Nus A is involved in transcriptional termination on lambda tI.
abstract: The transcriptional terminator tI generates the 3'end of the integrase (int) gene transcript that is read from the lambda PI promoter in lambda phage. We have studied the factors that affect transcription termination in vitro and in vivo at the lambda tI terminator. In vitro transcriptional studies showed that tI is about 80% efficient in the presence of purified NusA protein, whereas it is only about 50% efficient in its absence. In vivo studies, where the readthrough transcript of lambda tI was measured by quantitative dot blot analysis, gave about 80% efficiency in wild-type strains, but only 60% in the nusA1 mutant strain at non-permissive temperatures. These results support the idea that termination at lambda tI in vivo involves interaction with the NusA factor.
authors.affiliation: Departmento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., Mexico City, D.F.C.P., Mexico.
authors.forename: R M
authors.initials: RM
authors.lastname: Bermúdez-Cruz
authors.forename: M J
authors.initials: MJ
authors.lastname: Chamberlin
authors.forename: C
authors.initials: C
authors.lastname: Montañez
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D010582:Bacteriophage lambda / Q000235:genetics*; D001483:Base Sequence; D029968:Escherichia coli Proteins; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010445:Peptide Elongation Factors; D015719:Single-Strand Specific DNA and RNA Endonucleases / Q000378:metabolism; D013728:Terminator Regions, Genetic / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*; D035602:Transcriptional Elongation Factors; D014764:Viral Proteins / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D010445:Peptide Elongation Factors; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D014764:Viral Proteins; C068727:nusA protein, E coli; D015719:Single-Strand Specific DNA and RNA Endonucleases