title: The promoter architectural landscape of the Salmonella PhoP regulon.
abstract: The DNA-binding protein PhoP controls virulence and Mg²⁺ homeostasis in the Gram-negative pathogen Salmonella enterica serovar Typhimurium. PhoP regulates expression of a large number of genes that differ both in their ancestry and in the biochemical functions and physiological roles of the encoded products. This suggests that PhoP-regulated genes are differentially expressed. To understand how a bacterial activator might generate varied gene expression behaviour, we investigated the cis-acting promoter features (i.e. the number of PhoP binding sites, as well as their orientation and location with respect to the sites bound by RNA polymerase and the sequences that constitute the PhoP binding sites) in 23 PhoP-activated promoters. Our results show that natural PhoP-activated promoters utilize only a limited number of combinations of cis-acting features--or promoter architectures. We determine that PhoP activates transcription by different mechanisms, and that ancestral and horizontally acquired PhoP-activated genes have distinct promoter architectures.
authors.affiliation: Section of Microbial Pathogenesis, Yale School of Medicine, 295 Congress Avenue, 354D, New Haven, CT 06536, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Zwir
authors.forename: Tammy
authors.initials: T
authors.lastname: Latifi
authors.forename: J Christian
authors.initials: JC
authors.lastname: Perez
authors.forename: Henry
authors.initials: H
authors.lastname: Huang
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Groisman
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D018085:Regulon; D020218:Response Elements; D012480:Salmonella Infections / Q000382:microbiology*; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D001426:Bacterial Proteins; C061064:PhoP protein, Bacteria