REGULATION OF TOXIC SHOCK SYNDROME TOXIN-1 GENE IN STAPHYLOCOCCUS-AUREUS

Staphylococcus aureus produces various proteins in response to discret e signals from the external environment like many other pathogenic mic roorganisms. Certain staphylococcal exoproteins including toxic shock syndrome toxin-1 (TSST-1) are secreted according to the stimuli from t he environment, and the quantity synthesized is influenced by a number of different parameters. Using a transposon Tn551-mediated mutagenesi s, a mutant (RN 6390) defective in TSST-1 from synthesis was construct ed. TSST-1 from wild strain and mutant strain were purified and quanti tated from culture supernatants of Staphylococcus aureus. The mutant s train RN 6390 produced only 2% of TSST-1 compared with that produced b y the wild strain RN4282. Southern blot hybridization with a tsf (TSST -1 gene) probe indicated that the inactivated chromosomal locus is dis tinct from the tst. These results suggest that transposition by Tn551 inactivated a chromosomal locus whose activity was essential for the e xpression of the TSST-1 gene.