Abstract: Objective To investigate the mechanism of Porphyromonas gingivalis (P. gingivalis) transcription factor SinR and tyrosine kinase Ptk1 on the production of exopolysaccharide and the regulative relation between upstream and downstream. Methods The PCR fusion technique was employed to generate allelic exchange mutants of sinR (ΔsinR) and ptk1/sinR double deletion mutant (Δptk1/sinR) in ATCC 33277 . The exopolysaccharide production of Δptk1、ΔsinR and Δptk1/sinR strain of P. gingivalis with fluorescent lectins was detected by laser scanning confocal microscope (CLSM). Results Polysaccharide production of Δptk1 and Δptk1/sinR significantly decreased（P＜0.05）, while that of ΔsinR significantly increased, compared with wild strain P. gingivalis 33277（P＜0.05）. Conclusion These data suggest that SinR and Ptk1 have significant regulatory effects on of exopolysaccharide synthesis in P.gingivalis. In addition, Ptk1 functioned downstream of SinR for exopolysaccharide production in P. gingivalis.

Key words: P.gingivalis, extracellular polysaccharides, Ptk1, SinR