Porphyromonas gingivalis mutant defective in a putative extracytoplasmic function sigma factor shows a mutator...

Area of Science:

• Microbiology
• Molecular Biology

Background:

• Porphyromonas gingivalis is a key pathogen in chronic periodontitis.
• Bacteria use extracytoplasmic function (ECF) sigma factors to manage stress responses.
• PG1318 is an ECF sigma factor in P. gingivalis.

Purpose of the Study:

• To investigate the function of the ECF sigma factor PG1318 in P. gingivalis.
• To determine PG1318's role in regulating gene expression and mutation frequency.

Main Methods:

• Constructed a PG1318-defective mutant of P. gingivalis.
• Assessed hemagglutination and proteolytic activities.
• Utilized RT-PCR and southern blot analysis for gene transcription.
• Measured spontaneous mutation frequency.

Main Results:

• PG1318-defective mutants showed reduced proteolytic activity and non-pigmented colonies.
• Some mutants exhibited decreased transcription or deletion of the kgp gene.
• Mutation frequency conferring resistance to l-trifluoromethionine was significantly higher in the mutant.

Conclusions:

• PG1318 is involved in regulating mutation frequency in P. gingivalis.
• This sigma factor may play a role in maintaining genome stability under stress conditions.