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: Takemasa Maeda, Hiroshi Maeda, Kokoro Yamabe, Junji Mineshiba, Ichiro Tanimoto, Tadashi Yamamoto, Koji Naruishi, Susumu Kokeguchi, Shogo Takashiba
• Journal: FEMS immunology and medical microbiology (FEMS Immunol Med Microbiol) Vol. 58 Issue 2 Pg. 226-36 (Mar 2010) ISSN: 1574-695X [Electronic] England
• PMID: 19903198 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Bacterial
• Bacterial Proteins
• Recombinant Proteins
• Virulence Factors
• Mip-like protein, Chlamydia trachomatis

Topics

• Antibodies, Bacterial (blood)
• Bacterial Proteins (biosynthesis, genetics)
• Colony Count, Microbial
• Epithelial Cells (microbiology)
• Gene Deletion
• Gene Expression Regulation, Bacterial
• HeLa Cells
• Humans
• Nucleic Acid Hybridization
• Pasteurellaceae (genetics, pathogenicity)
• Periodontitis (immunology)
• Recombinant Proteins (genetics, immunology)
• Virulence
• Virulence Factors (biosynthesis, deficiency)