title: Regulation of sulfur assimilation pathways in Burkholderia cenocepacia through control of genes by the SsuR transcription factor.
abstract: The genome of Burkholderia cenocepacia contains two genes encoding closely related LysR-type transcriptional regulators, CysB and SsuR, involved in control of sulfur assimilation processes. In this study we show that the function of SsuR is essential for the utilization of a number of organic sulfur sources of either environmental or human origin. Among the genes upregulated by SsuR identified here are the tauABC operon encoding a predicted taurine transporter, three tauD-type genes encoding putative taurine dioxygenases, and atsA encoding a putative arylsulfatase. The role of SsuR in expression of these genes/operons was characterized through (i) construction of transcriptional reporter fusions to candidate promoter regions and analysis of their expression in the presence/absence of SsuR and (ii) testing the ability of SsuR to bind SsuR-responsive promoter regions. We also demonstrate that expression of SsuR-activated genes is not repressed in the presence of inorganic sulfate. A more detailed analysis of four SsuR-responsive promoter regions indicated that ~44 bp of the DNA sequence preceding and/or overlapping the predicted -35 element of such promoters is sufficient for SsuR binding. The DNA sequence homology among SsuR "recognition motifs" at different responsive promoters appears to be limited.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Łochowska
authors.forename: Roksana
authors.initials: R
authors.lastname: Iwanicka-Nowicka
authors.forename: Agata
authors.initials: A
authors.lastname: Zielak
authors.forename: Anna
authors.initials: A
authors.lastname: Modelewska
authors.forename: Mark S
authors.initials: MS
authors.lastname: Thomas
authors.forename: Monika M
authors.initials: MM
authors.lastname: Hryniewicz
mesh_terms: D019677:Artificial Gene Fusion; D001483:Base Sequence; D057508:Burkholderia cenocepacia / Q000235:genetics* / Q000378:metabolism*; D018983:DNA Footprinting; D024202:Electrophoretic Mobility Shift Assay; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006801:Humans; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D013455:Sulfur / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D014157:Transcription Factors; D013455:Sulfur