title: The csp operon of Streptococcus salivarius encodes two predicted cell-surface proteins, one of which, CspB, is associated with the fimbriae.
abstract: A Tn917 mutant library was generated to identify genes involved in the biogenesis of Streptococcus salivarius fimbriae. A fimbria-deficient mutant was isolated by negative selection using an immunomagnetic separation technique with specific anti-fimbriae polyclonal antibodies (pAbs). The transposon was inserted in an ORF, called orf176, which encoded a protein of unknown function. The transposon prevented the transcription of orf176 as well as two genes located downstream, which are designated cspA and cspB and which form the csp operon. Sequence analyses of CspA and CspB revealed that both proteins possessed the classic cell-wall-anchoring motif (LPXTG) of Gram-positive bacterial surface proteins. Recombinant CspA (rCspA) and CspB (rCspB) proteins were generated in Escherichia coli and used to produce pAbs. Immunolocalization experiments showed that anti-rCspB, but not anti-rCspA antibodies specifically recognized S. salivarius fimbriae. Our results suggested that the csp operon encoded predicted cell-surface proteins, one of which, CspB, was associated with the fimbriae.
authors.affiliation: Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire and Département de Biochimie et de Microbiologie, Université Laval, Québec, Canada G1K 7P4.
authors.forename: Céline
authors.initials: C
authors.lastname: Lévesque
authors.affiliation: Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire and Département de Biochimie et de Microbiologie, Université Laval, Québec, Canada G1K 7P4.
authors.forename: Christian
authors.initials: C
authors.lastname: Vadeboncoeur
authors.affiliation: Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire and Département de Biochimie et de Microbiologie, Université Laval, Québec, Canada G1K 7P4.
authors.forename: Michel
authors.initials: M
authors.lastname: Frenette
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D029968:Escherichia coli Proteins; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D015723:Gene Library; D005798:Genes, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D009876:Operon; D016601:RNA-Binding Proteins; D013291:Streptococcus / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C491179:CspB protein, E coli; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D016601:RNA-Binding Proteins; C062260:cold shock protein CS7.4, Bacteria; C077188:cold-shock protein CspB, Bacteria