Pleiotropic roles of iron-responsive transcriptional regulator Fur in Burkholderia multivorans

Abstract

The fur (ferric uptake regulator) gene of Burkholderia multivorans ATCC 17616 was identified by transposon mutagenesis analysis. The fur deletion mutant of strain ATCC 17616 (i) constitutively produced siderophores, (ii) was more sensitive to reactive oxygen species (ROS) than the wild-type strain, (iii) showed lower superoxide dismutase and catalase activities than the wild-type strain, (iv) was unable to grow on M9 minimal agar plates containing several substrates that can be used as sole carbon sources by the wild-type strain, and (v) was hypersensitive to nitrite and nitric oxide under microaerobic and aerobic conditions, respectively. These results clearly indicate that the Fur protein in strain ATCC 17616 plays pleiotropic roles in iron homeostasis, removal and/or resistance to ROS and nitrosative stress, and energy metabolism. Furthermore, employment of an in vivo Fur titration assay system led to the isolation from the ATCC 17616 genome of 13 Fur-binding DNA regions, and a subsequent electrophoretic mobility-shift assay confirmed the direct binding of Fur protein to all of these DNA regions. Transcriptional analysis of the genes located just downstream of the Fur-binding sites demonstrated that Fur acts as a repressor for these genes. Nine of the 13 regions were presumed to be involved in the acquisition and utilization of iron.

Complete Nucleotide Sequence of TOL Plasmid pDK1 Provides Evidence for Evolutionary History of IncP-7 Catabolic Plasmids

“…Bacterial strains and plasmids used in this study are listed in Table 1. Escherichia coli strains were grown at 37°C in Luria-Bertani (LB) broth (48), and Pseudomonas, Sphingomonas, and Burkholderia strains were grown at 30°C in LB broth diluted 1/3 (1/3-LB broth) (74). Solid media were prepared by the addition of 1.5% agar.…”

Identification of Burkholderia multivorans ATCC 17616 genetic determinants for fitness in soil by using signature-tagged mutagenesis

“…The fur product, a ferric uptake regulator, is a global transcriptional regulator for the iron regulon in many Gramnegative bacterial species (Faulkner & Helmann, 2011). As has been noted in other phylogenetically distant bacteria, the Fur protein in ATCC 17616 plays pleiotropic roles in the maintenance of iron homeostasis, removal and/or resistance to reactive oxygen species (ROS) and reactive nitrogen species (RNS), and energy metabolism of carbon and energy sources (Yuhara et al, 2008). We have also indicated that there is a higher level of ferric ion in the ATCC 17616 fur mutant, leading to the generation of a larger amount of very toxic ROS, i.e.…”

“…The amount of the singly inoculated control strain 2C4-34 did not change after the 20 to 40 day *In the second STM screening (see Table S2). DPositions and locus tag names used are on the basis of our deposited sequences [AP009385, AP009386 and AP009387 for Chr1, Chr2 and Chr3, respectively, in DDBJ/EMBL/GenBank databases Yuhara et al (2008)]. dNo name, no gene name associated with this ORF in the annotated ATCC 17616 genome.…”

Conjugal Transfer of Polychlorinated Biphenyl/Biphenyl Degradation Genes in Acidovorax sp. Strain KKS102, Which Are Located on an Integrative and Conjugative Element

“…1). The donor was mated with three recipient strains whose genome sequences have been determined: BmGm (a Gm-resistant derivative of B. multivorans ATCC 17616 [31,37]), Sp-UTKm (a Km-resistant derivative of Sphingobium japonicum UT26 [15]), and Pp-KTGm (a Gm-resistant derivative of P. putida KT2440 [16]). ATCC 17616 carries a Tn4371-like element, but UT26 and KT2440 do not.…”