title: Variation of expression defects in cell surface 190-kDa protein antigen of Streptococcus mutans.
abstract: Streptococcus mutans, which consists of four serotypes, c, e, f, and k, possesses a 190-kDa cell surface protein antigen (PA) for initial tooth adhesion. We used Western blot analysis to determine PA expression in 750 S. mutans isolates from 150 subjects and found a significantly higher prevalence of the isolates with PA expression defects in serotypes f and k compared to serotypes c and e. Moreover, the defect patterns could be classified into three types; no PA expression on whole bacterial cells and in their supernatant samples (Type N1), PA expression mainly seen in supernatant samples (Type N2), and only low expression of PA in the samples of whole bacterial cells (Type W). The underlying reasons for the defects were mutations in the gene encoding PA as well as in the transcriptional processing of this gene for Type N1, defects in the sortase gene for Type N2, and low mRNA expression of PA for Type W. Since cellular hydrophobicity and phagocytosis susceptibility of the PA-defective isolates were significantly lower than those of the normal expression isolates, the potential implication of such defective isolates in systemic diseases involving bacteremia other than dental caries was suggested. Additionally, multilocus sequence typing was utilized to characterize S. mutans clones that represented a proportion of isolates with PA defects of 65-100%. Therefore, we described the molecular basis for variation defects in PA expression of S. mutans. Furthermore, we also emphasized the strong association between PA expression defects and serotypes f and k as well as the clonal relationships among these isolates.
authors: Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand. Electronic address: jinthana.lap@mahidol.ac.th.
authors: Jinthana
authors: J
authors: Lapirattanakul
authors: Osaka University Graduate School of Dentistry, Osaka 565-0871, Japan.
authors: Ryota
authors: R
authors: Nomura
authors: Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8525, Japan.
authors: Michiyo
authors: M
authors: Matsumoto-Nakano
authors: Faculty of Dentistry, Mahidol University, Bangkok 10400, Thailand.
authors: Ratchapin
authors: R
authors: Srisatjaluk
authors: Osaka University Graduate School of Dentistry, Osaka 565-0871, Japan.
authors: Takashi
authors: T
authors: Ooshima
authors: Osaka University Graduate School of Dentistry, Osaka 565-0871, Japan.
authors: Kazuhiko
authors: K
authors: Nakano
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis* / Q000235:genetics; D015153:Blotting, Western; D015870:Gene Expression; D020869:Gene Expression Profiling; D014644:Genetic Variation; D006801:Humans; D008565:Membrane Proteins / Q000172:deficiency* / Q000235:genetics; D058885:Multilocus Sequence Typing; D065288:Serogroup; D013290:Streptococcal Infections / Q000382:microbiology; D013295:Streptococcus mutans / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000942:Antigens, Bacterial; D008565:Membrane Proteins
keywords: Cell surface protein antigen; Expression defect; MLST; S. mutans; Serotype