Identification of Fur-regulated genes in Actinobacillus actinomycetemcomitans

• Published in: Microbiology (Society for General Microbiology) 2006-03, Vol.152 (3), p.787-796
• Main Authors: Haraszthy, Violet I, Jordan, Shawn F, Zambon, Joseph J
• Format: Article
• Language: English
• Subjects: Actinobacillus actinomycetemcomitans; Aggregatibacter actinomycetemcomitans - genetics; Aggregatibacter actinomycetemcomitans - growth & development; Aggregatibacter actinomycetemcomitans - metabolism; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Drug Resistance, Bacterial; Escherichia; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Genetics; Hydrogen-Ion Concentration; Iron - metabolism; Manganese - pharmacology; Microbiology; Mutation; Regulon; Repressor Proteins - genetics; Repressor Proteins - metabolism
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.28366-0

1 Department of Restorative Dentistry, University at Buffalo, School of Dental Medicine, Buffalo, NY 14214, USA 2 Department of Periodontics and Endodontics, University at Buffalo, School of Dental Medicine, Buffalo, NY 14214, USA Correspondence Violet I. Haraszthy vh1{at}acsu.buffalo.edu Actinobacillus actinomycetemcomitans is an oral pathogen that causes aggressive periodontitis as well as sometimes life-threatening, extra-oral infections. Iron regulation is thought to be important in the pathogenesis of A. actinomycetemcomitans infections and, consistent with this hypothesis, the fur gene has recently been identified and characterized in A. actinomycetemcomitans . In this study, 14 putatively Fur-regulated genes were identified by Fur titration assay (Furta) in A. actinomycetemcomitans , including afuA , dgt , eno , hemA , tbpA , recO and yfe – some of which are known to be Fur regulated in other species. A fur mutant A. actinomycetemcomitans strain was created by selecting for manganese resistance in order to study the Fur regulon. Comparisons between the fur gene sequences revealed that nucleotide 66 changed from C in the wild-type to T in the mutant strain, changing leucine to isoleucine. The fur mutant strain expressed a nonfunctional Fur protein as determined by Escherichia coli -based ferric uptake assays and Western blotting. It was also more sensitive to acid stress and expressed higher levels of minC than the wild-type strain. minC , which inhibits cell division in other bacterial species and whose regulation by iron has not been previously described, was found to be Fur regulated in A. actinomycetemcomitans by Furta, by gel shift assays, and by RT-qPCR assays for gene expression. Abbreviations: Fur, ferric uptake regulator; Furta, Fur titration assay; RT-qPCR, real-time quantitative PCR