title: UlaR activates expression of the ula operon in Streptococcus pneumoniae in the presence of ascorbic acid.
abstract: In this study, the regulatory mechanism of the ula (utilization of l-ascorbic acid) operon, putatively responsible for transport and utilization of ascorbic acid in Streptococcus pneumoniae strain D39, is studied. β-Galactosidase assay data demonstrate that expression of the ula operon is increased in the presence of ascorbic acid as compared with the effects of other sugar sources including glucose. The ula operon consists of nine genes, including a transcriptional regulator UlaR, and is transcribed as a single transcriptional unit. We demonstrate the role of the transcriptional regulator UlaR as a transcriptional activator of the ula operon in the presence of ascorbic acid and show that activation of the ula operon genes by UlaR is CcpA-independent. Furthermore, we predict a 16 bp regulatory site (5'-AACAGTCCGCTGTGTA-3') for UlaR in the promoter region of ulaA. Deletion of the half or full UlaR regulatory site in PulaA confirmed that the UlaR regulatory site present in PulaA is functional.
authors.affiliation: Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Afzal
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, 17177, Stockholm, Sweden.
authors.forename: Sulman
authors.initials: S
authors.lastname: Shafeeq
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Nobels väg 16, 17177, Stockholm, Sweden.
authors.forename: Birgitta
authors.initials: B
authors.lastname: Henriques-Normark
authors.affiliation: Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands.
authors.forename: Oscar P
authors.initials: OP
authors.lastname: Kuipers
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism*; D001483:Base Sequence; D017124:Conserved Sequence; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D005947:Glucose / Q000378:metabolism; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D009876:Operon; D056510:Position-Specific Scoring Matrices; D011485:Protein Binding; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D014157:Transcription Factors; D005947:Glucose; D001205:Ascorbic Acid