title: Genome-Scale Mapping of Escherichia coli σ54 Reveals Widespread, Conserved Intragenic Binding.
abstract: Bacterial RNA polymerases must associate with a σ factor to bind promoter DNA and initiate transcription. There are two families of σ factor: the σ70 family and the σ54 family. Members of the σ54 family are distinct in their ability to bind promoter DNA sequences, in the context of RNA polymerase holoenzyme, in a transcriptionally inactive state. Here, we map the genome-wide association of Escherichia coli σ54, the archetypal member of the σ54 family. Thus, we vastly expand the list of known σ54 binding sites to 135. Moreover, we estimate that there are more than 250 σ54 sites in total. Strikingly, the majority of σ54 binding sites are located inside genes. The location and orientation of intragenic σ54 binding sites is non-random, and many intragenic σ54 binding sites are conserved. We conclude that many intragenic σ54 binding sites are likely to be functional. Consistent with this assertion, we identify three conserved, intragenic σ54 promoters that drive transcription of mRNAs with unusually long 5' UTRs.
authors.affiliation: Wadsworth Center, New York State Department of Health, Albany, New York, United States of America.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Bonocora
authors.affiliation: Wadsworth Center, New York State Department of Health, Albany, New York, United States of America.
authors.forename: Carol
authors.initials: C
authors.lastname: Smith
authors.affiliation: Wadsworth Center, New York State Department of Health, Albany, New York, United States of America.
authors.forename: Pascal
authors.initials: P
authors.lastname: Lapierre
authors.affiliation: Wadsworth Center, New York State Department of Health, Albany, New York, United States of America; Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, United States of America.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Wade
mesh_terms: D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics*; D016680:Genome, Bacterial; D011401:Promoter Regions, Genetic; D051877:RNA Polymerase Sigma 54 / Q000235:genetics*; D061785:Transcription Initiation, Genetic
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C497751:rpoN protein, E coli; D051877:RNA Polymerase Sigma 54