Related Experiment Video
Updated: Jun 12, 2026

Porphyromonas gingivalis as a Model Organism for Assessing Interaction of Anaerobic Bacteria with Host Cells
Published on: December 17, 2015
FimB regulates FimA fimbriation in Porphyromonas gingivalis
K Nagano1, Y Hasegawa, Y Murakami
1Department of Microbiology, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan. nagano@dpc.agu.ac.jp
Abstract:
The periodontitis-associated pathogen Porphyromonas gingivalis colonizes and forms a biofilm in gingival crevices through fimbriae. It is known that the often-used strains ATCC 33277 and 381 produce long FimA fimbriae. We found a possible nonsense mutation within fimB, immediately downstream from fimA, coding a major subunit of FimA fimbriae of the strains. Indeed, P. gingivalis strains, except for ATCC 33277 and 381, universally expressed FimB, the gene product of fimB. Electron micrographs revealed that a FimB-restored strain had short and dense, "toothbrush"-like, FimA fimbriae. FimA overexpression elongated the fimbriae, whereas FimB overexpression shortened them. FimB restoration increased production of FimA and its accessory proteins. Thus, FimB regulates the length and expression of FimA fimbriae. Additionally, FimB restoration significantly reduced the release of FimA fimbriae from the cell surface, suggesting that FimB functions as an anchor of the fimbriae. The restoration enhanced adherent activity as well.
Related Concept Videos
Fimbriae, Pili, and Axial Filaments
The Oral Microbiota
Mechanism of Filopodia Formation
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Biofilms
Gene Regulation in Microbial Communities: Quorum Sensing
Cytoskeletal Proteins in Bacteria