Regulation of Sulfur Assimilation Pathways in
            <i>Burkholderia cenocepacia</i>
            : Identification of Transcription Factors CysB and SsuR and Their Role in Control of Target Genes

Iwanicka-Nowicka, Roksana; Zielak, Agata; Cook, Anne M.; Thomas, Mark S.; Hryniewicz, Monika M.

doi:10.1128/jb.00592-06

Cited by 22 publications

(32 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These findings imply that O-acetylserine does not affect the nature of DNA binding of CysB DS1 . In previous studies, the function of CysB of Burkholderia cenocepacia appeared to be independent of the presence of O-acetylserine (16); therefore, CysB may vary with respect to the recognition of an inducer.…”

Section: Discussionmentioning

confidence: 99%

“…The finding of SfnR implied that sulfone utilization of DS1 is controlled by a novel mechanism for the sulfate starvation response because all of the other known transcriptional regulators of gram-negative bacteria involved in organosulfur metabolism belong to the LysR family, e.g., Cbl and SdsB (5), AsfR (40), SftR (18), and SsuR (16). More interestingly, SfnR lacks an N-terminal regulatory domain, unlike many other 54 -dependent transcriptional regulators (8,9).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Transcription Factors CysB and SfnR Constitute the Hierarchical Regulatory System for the Sulfate Starvation Response inPseudomonas putida

et al. 2008

View full text Add to dashboard Cite

Pseudomonas putida DS1 is able to utilize dimethyl sulfone as a sulfur source. Expression of the sfnFG operon responsible for dimethyl sulfone oxygenation is directly regulated by a 54 -dependent transcriptional activator, SfnR, which is encoded within the sfnECR operon. We investigated the transcription mechanism for the sulfate starvation-induced expression of these sfn operons. Using an in vivo transcription assay and in vitro DNAbinding experiments, we revealed that SfnR negatively regulates the expression of sfnECR by binding to the downstream region of the transcription start point. Additionally, we demonstrated that a LysR-type transcriptional regulator, CysB, directly activates the expression of sfnECR by binding to its upstream region. CysB is a master regulator that controls the sulfate starvation response of the sfn operons, as is the case for the sulfonate utilization genes of Escherichia coli, although CysB DS1 appeared to differ from that of E. coli CysB in terms of the effect of O-acetylserine on DNA-binding ability. Furthermore, we investigated what effector molecules repress the expression of sfnFG and sfnECR in vivo by using the disruptants of the sulfate assimilatory genes cysNC and cysI. The measurements of mRNA levels of the sfn operons in these gene disruptants suggested that the expression of sfnFG is repressed by sulfate itself while the expression of sfnECR is repressed by the downstream metabolites in the sulfate assimilatory pathway, such as sulfide and cysteine. These results indicate that SfnR plays a role independent of CysB in the sulfate starvation-induced expression of the sfn operons.Sulfur, an essential element for bacterial growth, is assimilated from a range of sources. The preferred sulfur source for bacteria is inorganic sulfate, but in soil environments, sulfate may not be freely available because inorganic sulfate constitutes less than 5% of the total sulfur (1). The remainder is largely in the form of sulfate esters and carbon-bound sulfur such as peptides/amino acids and sulfonates (1). Volatile organic sulfur compounds, for example, dimethyl sulfide (DMS) and methanethiol, are also widely distributed in the environment because they are emitted from oceans (2), freshwater sediments (28, 29), and soils (26, 31). Thus, several soil bacterial species have developed a number of systems that allow the use of these organosulfur compounds.Metabolic use of these organosulfur compounds, especially alkanesulfonates, taurine, and alkanesulfate ester, has been extensively investigated in Escherichia coli and Pseudomonas spp. (reviewed in reference 19). Bacterial organosulfur assimilation is mediated by the sulfate starvation response, which involves a set of proteins synthesized by several species of bacteria when the supply of their preferred sulfur sources, such as inorganic sulfate, cysteine, and thiosulfate, is limited. These proteins are known as sulfate starvation-induced (SSI) proteins and include enzymes and transport systems for scavenging sulfur from organic compounds (19...

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Transcription Factors CysB and SfnR Constitute the Hierarchical Regulatory System for the Sulfate Starvation Response inPseudomonas putida

et al. 2008

View full text Add to dashboard Cite

show abstract

“…B. cenocepacia strains used in this study are shown in Table 1. Growth conditions were essentially the same as those described previously (18). The modified sulfur-free M9 medium was supplemented with the alternative sole sulfur sources listed in Table 2, used at a concentration of 0.25 mM (sodium salts) each or 0.1 mM for L-cystine or L-methionine.…”

Section: Methodsmentioning

confidence: 99%

“…We noticed that the functions of B. cenocepacia CysB and SsuR may partially replace each other in the regulation of some target promoters, e.g., sbp P and cysI P (controlling expression of the sbp cysTWA operon encoding the sulfate transporter and the cysIXHD 1 NG operon encoding sulfate activation and reduction functions, respectively). One example of a B. cenocepacia promoter upregulated specifically by SsuR was identified as ssuD P , preceding the ssuDBC cluster that encodes aliphatic sulfonate transport and desulfonation functions (18).…”

mentioning

confidence: 99%

“…In our previous study (18), we started a systematic experimental characterization of sulfur assimilation-related processes and their regulation in B. cenocepacia. Using the B. cenocepacia strain 715j (an isolate from a CF patient), we have identified two cysB-like genes encoding LysR-type transcription factors sharing homology with CysB and Cbl of E. coli as well as significant mutual homology.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Regulation of Sulfur Assimilation Pathways in Burkholderia cenocepacia through Control of Genes by the SsuR Transcription Factor

Łochowska¹,

Iwanicka-Nowicka²,

Zielak³

et al. 2011

Journal of Bacteriology

View full text Add to dashboard Cite

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 ϳ44 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.

show abstract

Identification of quorum sensing‐controlled genes in Burkholderia ambifaria

et al. 2013

View full text Add to dashboard Cite

The Burkholderia cepacia complex (Bcc) comprises strains with a virulence potential toward immunocompromised patients as well as plant growth–promoting rhizobacteria (PGPR). Owing to the link between quorum sensing (QS) and virulence, most studies among Bcc species have been directed toward QS of pathogenic bacteria. We have investigated the QS of B. ambifaria, a PGPR only infrequently recovered from patients. The cepI gene, responsible for the synthesis of the main signaling molecule N-octanoylhomoserine lactone (C8-HSL), was inactivated. Phenotypes of the B. ambifaria cepI mutant we observed, such as increased production of siderophores and decreased proteolytic and antifungal activities, are in agreement with those of other Bcc cepI mutants. The cepI mutant was then used as background strain for a whole-genome transposon-insertion mutagenesis strategy, allowing the identification of 20 QS-controlled genes, corresponding to 17 loci. The main functions identified are linked to antifungal and antimicrobial properties, as we have identified QS-controlled genes implicated in the production of pyrrolnitrin, burkholdines (occidiofungin-like molecules), and enacyloxins. This study provides insights in the QS-regulated functions of a PGPR, which could lead to beneficial potential biotechnological applications.

show abstract

Regulation of Sulfur Assimilation Pathways in Burkholderia cenocepacia : Identification of Transcription Factors CysB and SsuR and Their Role in Control of Target Genes

Cited by 22 publications

References 56 publications

Transcription Factors CysB and SfnR Constitute the Hierarchical Regulatory System for the Sulfate Starvation Response inPseudomonas putida

Transcription Factors CysB and SfnR Constitute the Hierarchical Regulatory System for the Sulfate Starvation Response inPseudomonas putida

Regulation of Sulfur Assimilation Pathways in Burkholderia cenocepacia through Control of Genes by the SsuR Transcription Factor

Identification of quorum sensing‐controlled genes in Burkholderia ambifaria

Contact Info

Product

Resources

About