TY - JOUR
T1 - The bfeR regulator mediates enterobactin-inducible expression of Bordetella enterobactin utilization genes
AU - Anderson, Mark T.
AU - Armstrong, Sandra K
PY - 2004/11
Y1 - 2004/11
N2 - Utilization of the enterobactin siderophore by the respiratory pathogens Bordetella pertussis and Bordetella bronchiseptica is dependent on the BFeA outer membrane receptor. This study determined that production of BfeA was increased significantly in iron-starved bacteria upon supplementation of cultures with enterobactin. A 1.01-kb open reading frame, designated bfeR, encoding a predicted positive transcriptional regulator of the AraC family was identified upstream and divergently oriented from bfeA. In iron-depleted cultures containing enterobactin, a Bordetella bfeR mutant exhibited markedly decreased BfeA receptor production compared to that of the wild-type strain. Additionaliy, B. pertussis and B. bronchiseptica bfeR mutants exhibited impaired growth with ferric enterobactin as the sole source of iron, demonstrating that effective enterobactin utilization is bfeR dependent. Transcriptional analysis using bfeA-lacZ reporter fusions in wild-type strains demonstrated that bfeA transcription was stimulated in iron-depleted conditions in the presence of enterobactin, compared to modest expression levels in cultures lacking enterobactin. In contrast, bfeA transcription in B. pertussis and B. bronchiseptica bfeR mutants was completely unresponsive to the enterobactin inducer. bfeA transcriptional analyses of a bfeA mutant demonstrated that induction by enterobactin did not require BfeA receptor-mediated uptake of the siderophore. These studies establish that bfeR encodes an enterobactin-dependent positive regulator of bfeA transcription in these Bordetella species.
AB - Utilization of the enterobactin siderophore by the respiratory pathogens Bordetella pertussis and Bordetella bronchiseptica is dependent on the BFeA outer membrane receptor. This study determined that production of BfeA was increased significantly in iron-starved bacteria upon supplementation of cultures with enterobactin. A 1.01-kb open reading frame, designated bfeR, encoding a predicted positive transcriptional regulator of the AraC family was identified upstream and divergently oriented from bfeA. In iron-depleted cultures containing enterobactin, a Bordetella bfeR mutant exhibited markedly decreased BfeA receptor production compared to that of the wild-type strain. Additionaliy, B. pertussis and B. bronchiseptica bfeR mutants exhibited impaired growth with ferric enterobactin as the sole source of iron, demonstrating that effective enterobactin utilization is bfeR dependent. Transcriptional analysis using bfeA-lacZ reporter fusions in wild-type strains demonstrated that bfeA transcription was stimulated in iron-depleted conditions in the presence of enterobactin, compared to modest expression levels in cultures lacking enterobactin. In contrast, bfeA transcription in B. pertussis and B. bronchiseptica bfeR mutants was completely unresponsive to the enterobactin inducer. bfeA transcriptional analyses of a bfeA mutant demonstrated that induction by enterobactin did not require BfeA receptor-mediated uptake of the siderophore. These studies establish that bfeR encodes an enterobactin-dependent positive regulator of bfeA transcription in these Bordetella species.
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U2 - 10.1128/JB.186.21.7302-7311.2004
DO - 10.1128/JB.186.21.7302-7311.2004
M3 - Article
C2 - 15489442
AN - SCOPUS:6044276736
SN - 0021-9193
VL - 186
SP - 7302
EP - 7311
JO - Journal of bacteriology
JF - Journal of bacteriology
IS - 21
ER -