title: The argRB of Escherichia coli is rare in isolates obtained from natural sources.
abstract: A single nucleotide polymorphism between Escherichia coli strains K12 and B is known to alter the mechanism by which the arginine repressor regulates arginine biosynthesis, from a regulated system in E. coli K12 to a deregulated system in E. coli B. Laboratory experiments have demonstrated that the different regulatory strategies are selectively favored under different environmental conditions. In this study we analyzed 537 E. coli strains and show that the argR allele in E. coli B, which causes deregulation, is rare in isolates obtained from natural sources. Moreover, sequence analysis of 85 strains shows no evidence of selection at the arginine repressor locus. This illustrates that analysis of sequence data is insufficient to detect selection of uncommon alleles in rare environments.
authors.affiliation: University of Minnesota, Department of Ecology, Evolution, and Behavior, Saint Paul, MN, USA. lauren.merlo@gmail.com
authors.forename: Lauren M F
authors.initials: LM
authors.lastname: Merlo
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sadowsky
authors.forename: John A
authors.initials: JA
authors.lastname: Ferguson
authors.forename: Antony M
authors.initials: AM
authors.lastname: Dean
mesh_terms: D000483:Alleles; D000818:Animals; D000829:Animals, Domestic / Q000382:microbiology; D000835:Animals, Wild / Q000382:microbiology; D001120:Arginine / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D018388:Codon, Terminator; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D005787:Gene Frequency; D005798:Genes, Bacterial; D014644:Genetic Variation; D006239:Haplotypes; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D020539:Sequence Analysis, Protein
chemical_list: D018388:Codon, Terminator; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D001120:Arginine