title: Regulation of Streptococcus mutans PTS Bio by the transcriptional repressor NigR.
abstract: Streptococcus mutans is implicated in human dental caries, and the carbohydrate metabolism of this organism plays an important role in the formation of this disease. Carbohydrate transport and metabolism are essential for the survival of S. mutans in the oral cavity. It is known that a unique phosphoenolpyruvate-sugar phosphotransferase system PTS(B) (io) of S. mutans UA159 is expressed in sucrose-grown biofilms (Mol Oral Microbiol 28: 2013; 114). In this study we analyzed the transcriptional regulation of the operon (O(B) (io) ) encoding the PTS(B) (io) and showed that it was repressed by NigR, a LacI-like transcriptional regulator. Using electro-mobility shift assay, we described two operators to which NigR bound with different affinities. We also identified the transcriptional start site and showed that one of the operators overlaps with the promoter and presumably represses initiation of transcription. Mutational analyses revealed the key nucleotides in the operators required for high-affinity binding of NigR. PTS(B) (io) is expressed in S. mutans biofilms so understanding its regulation may provide improved strategies for caries treatment and prevention.
authors.affiliation: Miller School of Medicine, University of Miami, Miami, FL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Vujanac
authors.affiliation: Miller School of Medicine, University of Miami, Miami, FL, USA.
authors.forename: V S
authors.initials: VS
authors.lastname: Iyer
authors.affiliation: Miller School of Medicine, University of Miami, Miami, FL, USA.
authors.forename: M
authors.initials: M
authors.lastname: Sengupta
authors.affiliation: Miller School of Medicine, University of Miami, Miami, FL, USA.
authors.forename: D
authors.initials: D
authors.lastname: Ajdic
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms; D001692:Biological Transport / Q000235:genetics; D003731:Dental Caries / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D056968:Lac Repressors / Q000235:genetics; D016296:Mutagenesis; D009875:Operator Regions, Genetic; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013295:Streptococcus mutans / Q000235:genetics* / Q000378:metabolism; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D056968:Lac Repressors; D012097:Repressor Proteins; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System
keywords: Streptococcus mutans; dental caries; phosphotransferase system; transcriptional regulation