Targeted regulation of pathogenic properties in streptococci

For the study of targeted regulation of pathogenic properties in streptococci, the following biological models were selected: DNA-binding regulatory protein Sak189ofS. agalactiae, and DNA-binding regulatory proteins MutR and Rgg of S. pyogenes. The mutR, rgg, andsak189 isogenic mutants were generated. It was shown that inact ivation of transcriptional regulatory genes resulted in the changes in growth kinetics, an ability of the strains to utilize substrates and to grow in the rich and chemically defined media. The Rgg-regulons were identified in three 5. pyogenes strains. The certain differences in the expression of surface and secreted virulence proteins were found in mutant strains compared to the parental strains. Finally, it was demonstrated that inactivation of sakl89, mutR, and rgg genes affected pathogenic properties of streptococci in vitro and in vivo.