Characterization of essential enolase in Staphylococcus aureus

In this study, we characterized the essentiality of enolase for growth of Staphylococcus aureus in vitro by using a TetR-regulated antisense RNA expression technology. The induced enolase antisense RNA dramatically decreased the production of enolase, which in turn inhibited the growth of S. aureus. In addition, we found that the down-regulation of eno expression can effectively inhibit Triton X-100-induced lysis and alleviate penicillin-caused cell lysis. To further confirm the specific effect of enolase on autolysis, we constructed an enolase over-expression system and demonstrated that the over-expression of enolase enhances both Triton X-100 and penicillin-induced cell lysis without increasing cell growth rate. We also performed hydrolase induced autolysis and zymographic assays and found that enolase had no impact on either bacterial sensitivity to hydrolase or hydrolase activity. Moreover, we found that the down-regulating expression of enolase selectively increased bacterial sensitivity to phosphomycin. Taken together, the above results suggest that the enolase is essential for S. aureus and involved in the process of bacterial autolysis.