title: The putative autolysin regulator LytR in Streptococcus mutans plays a role in cell division and is growth-phase regulated.
abstract: Streptococcus mutans is the primary odontopathogen present in supragingival plaque and causes the oral disease known as dental caries. Colonization of the oral cavity by S. mutans requires the bacteria to adhere to the tooth surface and occurs by both sucrose-dependent and -independent mechanisms. Sucrose-independent adhesion of S. mutans in vitro has been shown to involve an ORF (ORF0317) encoding a homologue (39 %) to LytR, a regulator of autolysin activity in Bacillus subtilis. The protein encoded by ORF0317, LytR, belongs to the LytR/CpsA/Psr protein family. This family has a putative role in cell-wall structural maintenance, possibly through autolysin regulation. Autolysins have also been shown to be important in surface adhesion in Lactococcus lactis and in the pathogenic properties of Streptococcus pneumoniae. To investigate the role of autolysins in the adhesion and pathogenesis of S. mutans, a LytR mutant was constructed. The mutant grows in long chains, which may indicate a defect in cell division. Further experiments with the mutant strain show increased autolytic activity, indicating that LytR attenuates S. mutans autolytic activity, possibly through regulation of the expression of autolytic enzymes. No defect in cell-to-surface adherence or biofilm growth was seen in the LytR mutant. However, a connection between cell growth phase and transcription of lytR was found.
authors.affiliation: in the Aab Institute for Biomedical Sciences and Department of Microbiology and Immunology, University of Rochester, Rochester, NY 14642, USA.
authors.forename: Christa H
authors.initials: CH
authors.lastname: Chatfield
authors.affiliation: Eastman Department of Dentistry, University of Rochester, Rochester, NY 14642, USA.|Center for Oral Biology, University of Rochester, Rochester, NY 14642, USA.
authors.forename: Hyun
authors.initials: H
authors.lastname: Koo
authors.affiliation: in the Aab Institute for Biomedical Sciences and Department of Microbiology and Immunology, University of Rochester, Rochester, NY 14642, USA.|Center for Oral Biology, University of Rochester, Rochester, NY 14642, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Quivey
mesh_terms: D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D002455:Cell Division; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000378:metabolism*; D013295:Streptococcus mutans / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C093500:LytR protein, Staphylococcus aureus; D014157:Transcription Factors; D009238:N-Acetylmuramoyl-L-alanine Amidase