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The effect of environmental conditions on expression of Bacteroides fragilis and Bacteroides thetaiotaomicron C10 protease genes
Thornton, Roibeard F.; Murphy, Elizabeth C.; Kagawa, Todd F.; O'Toole, Paul W.; Cooney, Jakki C.
Background: Bacteroides fragilis and Bacteroides thetaiotaomicron are members of the normal human intestinal microbiota. However, both organisms are capable of causing opportunistic infections, during which the environmental conditions to which the bacteria are exposed change dramatically. To further explore their potential for contributing to infection, we have characterized the expression in B. thetaiotaomicron of four homologues of the gene encoding the C10 cysteine protease SpeB, a potent extracellular virulence factor produced by Streptococcus pyogenes. Results: We identified a paralogous set of genes (btp genes) in the B. thetaiotaomicron genome, that were related to C10 protease genes we recently identified in B. fragilis. Similar to C10 proteases found in B. fragilis, three of the B. thetaiotaomicron homologues were transcriptionally coupled to genes encoding small proteins that are similar in structural architecture to Staphostatins, protease inhibitors associated with Staphopains in Staphylococcus aureus. The expression of genes for these C10 proteases in both B. fragilis and B. thetaiotaomicron was found to be regulated by environmental stimuli, in particular by exposure to oxygen, which may be important for their contribution to the development of opportunistic infections. Conclusions: Genes encoding C10 proteases are increasingly identified in operons which also contain genes encoding proteins homologous to protease inhibitors. The Bacteroides C10 protease gene expression levels are responsive to different environmental stimuli suggesting they may have distinct roles in the bacterial-host interaction.
Keyword(s): Bacteroides fragilis; DNA
Publication Date:
2012
Type: Journal article
Peer-Reviewed: Yes
Language(s): English
Institution: University of Limerick
Funder(s): Science Foundation Ireland; Irish Research Council for Science Engineering and Technology
Citation(s): BMC Microbiology;12: 190
http://www.biomedcentral.com/1471-2180/12/190
08/RFP/BMT1596
Publisher(s): BioMed Central
First Indexed: 2014-04-03 05:38:02 Last Updated: 2018-07-25 06:45:02