title: Rsd family proteins make simultaneous interactions with regions 2 and 4 of the primary sigma factor.
abstract: Bacterial anti-sigma factors typically regulate sigma factor function by restricting the access of their cognate sigma factors to the RNA polymerase (RNAP) core enzyme. The Escherichia coli Rsd protein forms a complex with the primary sigma factor, sigma(70), inhibits sigma(70)-dependent transcription in vitro, and has been proposed to function as a sigma(70)-specific anti-sigma factor, thereby facilitating the utilization of alternative sigma factors. In prior work, Rsd has been shown to interact with conserved region 4 of sigma(70), but it is not known whether this interaction suffices to account for the regulatory functions of Rsd. Here we show that Rsd and the Rsd orthologue AlgQ, a global regulator of gene expression in Pseudomonas aeruginosa, interact with conserved region 2 of sigma(70). We show further that Rsd and AlgQ can interact simultaneously with regions 2 and 4 of sigma(70). Our findings establish that the abilities of Rsd and AlgQ to interact with sigma(70) region 2 are important determinants of their in vitro and in vivo activities.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Andy H
authors.initials: AH
authors.lastname: Yuan
authors.forename: Brian D
authors.initials: BD
authors.lastname: Gregory
authors.forename: Josh S
authors.initials: JS
authors.lastname: Sharp
authors.forename: Katherine D
authors.initials: KD
authors.lastname: McCleary
authors.forename: Simon L
authors.initials: SL
authors.lastname: Dove
authors.forename: Ann
authors.initials: A
authors.lastname: Hochschild
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D009154:Mutation; D010957:Plasmids; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism; D011710:Pyocyanine / Q000096:biosynthesis; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C079502:AlgQ protein, Pseudomonas aeruginosa; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012097:Repressor Proteins; D012808:Sigma Factor; D015534:Trans-Activators; D011710:Pyocyanine; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases