Characterization of genes homologous to the general stress-inducible gene gls24 in Enterococcus faecalis and Lactococcus lactis.

Three genes (Ef0604, ymgG, and ytgH) were identified as homologous to the gls24 gene (encoding the general stress protein Gls24) in Enterococcus faecalis V583 and Lactococcus lactis IL1403 genomes sequences, and therefore are part of the 'gls24 family'. The other proteins encoded by the different surrounding genes in each of their respective operons are also highly similar. Our transcriptional analysis showed that Ef0604 and ymgG are not induced under the stress conditions tested. On the other hand, ytgH is induced at the onset of glucose starvation and by heat, ethanolic, osmotic, and CdCl(2) stresses. The transcriptional start site of this operon was identified and the promoter region appears to contain an 'extended -10 Box'. Moreover, the over-expression under several stress conditions of the YtgH protein observed on 2D gel electrophoresis confirms that it corresponds to a general stress protein in L. lactis.