title: Highly expressed genes in a rough-colony-forming phenotype of Aggregatibacter actinomycetemcomitans: implication of a mip-like gene for the invasion of host tissue.
abstract: Aggregatibacter actinomycetemcomitans, a potent pathogen of periodontitis, typically grows as a rough and adherent colony on primary isolated cultures. The colony transforms into a smooth phenotype during repeated subculture. In this study, we aimed to identify highly expressed genes in the rough-colony-forming phenotype for isolation of host-induced genes. Using a cDNA-subtractive hybridization technique, three genes, homologous to a macrophage infectivity potentiator gene (mip), peroxiredoxin gene (prx) and outer membrane protein gene (ompA), were identified. The expression levels of these genes in the rough-colony-forming phenotype were 4-10-fold higher as compared with the smooth-colony-forming phenotype. Attention was focused on the mip-like gene, and a recombinant protein and a deficient mutant were constructed. The recombinant protein reacted with sera from patients with periodontitis, suggesting the production of the Mip-like protein in periodontal lesions. Viable quantitative invasion assay demonstrated that the viable cell counts of the wild-type strain that invaded HeLa cells were more than fourfold as compared with the mip-deficient mutant. The expression of the mip-like gene, prx-like gene and ompA-like gene may be enhanced in the host, and the mip-like gene may play an important role in the infection of A. actinomycetemcomitans, especially in its invasion of the epithelium.
authors.affiliation: Department of Patho-Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Takemasa
authors.initials: T
authors.lastname: Maeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Maeda
authors.forename: Kokoro
authors.initials: K
authors.lastname: Yamabe
authors.forename: Junji
authors.initials: J
authors.lastname: Mineshiba
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tanimoto
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Naruishi
authors.forename: Susumu
authors.initials: S
authors.lastname: Kokeguchi
authors.forename: Shogo
authors.initials: S
authors.lastname: Takashiba
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D015169:Colony Count, Microbial; D004847:Epithelial Cells / Q000382:microbiology; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006367:HeLa Cells; D006801:Humans; D009693:Nucleic Acid Hybridization; D015661:Pasteurellaceae / Q000235:genetics* / Q000472:pathogenicity*; D010518:Periodontitis / Q000276:immunology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D014774:Virulence; D037521:Virulence Factors / Q000096:biosynthesis* / Q000172:deficiency
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D011994:Recombinant Proteins; D037521:Virulence Factors; C077482:Mip-like protein, Chlamydia trachomatis