Transcriptional analysis of the groE and dnaK heat-shock operons of Enterococcus faecalis.

Enterococcus faecalis is able to survive in extremely adverse conditions, and its ability to resist stress is considered a key virulence attribute. Here, we conducted a detailed transcriptional analysis of the groE and dnaK operons of E. faecalis. The dnaK operon is comprised of four genes (hrcA-grpE-dnaK-dnaJ) preceded by two conserved CIRCE sequences. The dnaK operon is expressed from a sigmaA-type promoter located upstream of hrcA and multiple transcripts are detectable, possibly due to mRNA processing. The groE operon (groES-groEL) is transcribed as a single mRNA from a sigmaA-type promoter located immediately upstream of a CIRCE element. Induction of dnaK and groEL occurs in response to heat shock and exposure to NaCl, SDS and H(2)O(2).