The dissemination of C10 cysteine protease genes in Bacteroides fragilis species by mobile genetic elements
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Published Version
Date
2010-04-23
Authors
Thornton, Roibeard F.
Kagawa, Todd F.
O'Toole, Paul W.
Cooney, Jakki C.
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Published Version
Abstract
Background: The C10 family of cysteine proteases includes enzymes that contribute to the virulence of bacterial
pathogens, such as SpeB in Streptococcus pyogenes. The presence of homologues of cysteine protease genes in human
commensal organisms has not been examined. Bacteroides fragilis is a member of the dominant Bacteroidetes phylum
of the human intestinal microbiota, and is a significant opportunistic pathogen.
Results: Four homologues of the streptococcal virulence factor SpeB were identified in the B. fragilis genome. These
four protease genes, two were directly contiguous to open reading frames predicted to encode staphostatin-like
inhibitors, with which the protease genes were co-transcribed. Two of these protease genes are unique to B. fragilis 638R and are associated with two large genomic insertions. Gene annotation indicated that one of these insertions was a conjugative Tn-like element and the other was a prophage-like element, which was shown to be capable of excision. Homologues of the B. fragilis C10 protease genes were present in a panel of clinical isolates, and in DNA extracted from normal human faecal microbiota.
Conclusions: This study suggests a mechanism for the evolution and dissemination of an important class of protease in major members of the normal human microbiota.
Description
Keywords
C10 , Cysteine Proteases , Streptococcus pyogenes , Bacteroides fragilis , SpeB , Human Microbiota
Citation
Thornton, R, T.F. Kagawa, P.W. O’Toole and J.C. Cooney. 2010. The dissemination of C10 cysteine protease genes in Bacteroides fragilis species by mobile genetic elements. BMC Microbiol. 10: 122. DOI: 10.1186/1471-2180-10-122