title: Specificity of antitermination mechanisms. Suppression of the terminator cluster T1-T2 of Escherichia coli ribosomal RNA operon, rrnB, by phage lambda antiterminators.
abstract: Transcription of the ribosomal RNA operons (rrn) in Escherichia coli is subject to an antitermination mechanism whereby RNA polymerase is modified to a termination-resistant form during transit through the rrn leader region. This antitermination mechanism is unable to overcome the T1-T2 terminator cluster located at the end of an rrn operon, such as rrnB. We have tested the specificity with which the T1-T2 terminators override an antitermination mechanism, by placing the terminator cluster downstream from the nut and qut sites recognized by phage lambda N and Q gene antiterminators, respectively. Measurement of downstream gene expression shows that RNA polymerase modified by either N or Q reads through the T1-T2 terminators quite efficiently. This supports the view that T1-T2 are not superterminators, and that the rrn antitermination mechanism may have a restricted terminator specificity.
authors.affiliation: Department of Microbiology, University of Connecticut Health Center, Farmington 06030.
authors.forename: B
authors.initials: B
authors.lastname: Ghosh
authors.forename: E
authors.initials: E
authors.lastname: Grzadzielska
authors.forename: P
authors.initials: P
authors.lastname: Bhattacharya
authors.forename: E
authors.initials: E
authors.lastname: Peralta
authors.forename: J
authors.initials: J
authors.lastname: DeVito
authors.forename: A
authors.initials: A
authors.lastname: Das
mesh_terms: D010582:Bacteriophage lambda / Q000235:genetics*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D009876:Operon; D012329:RNA, Bacterial / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics*; D013728:Terminator Regions, Genetic; D014764:Viral Proteins / Q000378:metabolism; D054334:Viral Regulatory and Accessory Proteins / Q000378:metabolism
chemical_list: C059417:N protein, Bacteriophage lambda; C066119:Q protein, Bacteriophage lambda; D012329:RNA, Bacterial; D012335:RNA, Ribosomal; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; D012321:DNA-Directed RNA Polymerases