Actinobacillus pleuropneumoniae Iron Transport: a Set of exbBD Genes Is Transcriptionally Linked to the tbpB Gene and Required for Utilization of Transferrin-Bound Iron
AUTOR(ES)
Tonpitak, Walaiporn
FONTE
American Society for Microbiology
RESUMO
Upon iron restriction, Actinobacillus pleuropneumoniae has been shown to express the transferrin-binding proteins TbpB and TbpA, both of which have been implied to be important virulence factors. In order to identify additional iron-regulated proteins, we cloned and analyzed the region upstream of the transferrin-binding protein genes in an A. pleuropneumoniae serotype 7 strain. We located immediately upstream of the tbpB gene two open reading frames which were 43% homologous to the neisserial ExbBD protein genes. By raising specific antibodies, we showed that ExbB is expressed under iron-limiting growth conditions only, and RT-PCR analysis revealed that the exbBD genes and the tbpB gene are transcribed on a single polycistronic mRNA. By constructing an isogenic and nonpolar exbBD mutant, we showed that the exbBD genes are required by A. pleuropneumoniae for utilization of transferrin-bound iron. Using PCR and Western blotting, we showed that the genetic organization found in A. pleuropneumoniae serotype 7 is similar in all 12 A. pleuropneumoniae serotype reference strains.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=97262Documentos Relacionados
- Utilization of transferrin-bound iron by Haemophilus influenzae requires an intact tonB gene.
- Haemophilus somnus Possesses Two Systems for Acquisition of Transferrin-Bound Iron
- Effect of sulphydryl inhibition on the uptake of transferrin-bound iron by reticulocytes
- Characterization of the exbBD operon of Escherichia coli and the role of ExbB and ExbD in TonB function and stability.
- Relative availability of transferrin-bound iron and cell-derived iron to aerobactin-producing and enterochelin-producing strains of Escherichia coli and to other microorganisms.