Evidence for multiple levels of regulation of Oenococcus oeni clpPclpL locus expression in response to stress

Abstract

A locus containing the clpP and clpL genes in the lactic acid bacterium Oenococcus oeni was studied. Real-time reverse transcription-PCR analysis revealed different induction factors involved in expression of these genes during stress. According to the conditions, clpP and clpL genes could be transcripted as two distinct transcripts or cotranscripted. The clpP promoter depended on the CtsR regulator, but surprisingly the clpL promoter did not. The amount of the clpL transcript depended on mRNA stability. This clp ATPase gene is at least controlled at the posttranscriptional level. Stress response plays a key role in the cell adaptation of all organisms to environmental conditions. To survive environmental changes, cells synthesize proteins, including both chaperones and proteases, above all to prevent accumulation of abnormal proteins (20). These stress proteins are also involved in various cellular regulations during growth (28). Recent studies have focused on a large family of proteins, named Clp (for caseinolytic protein), which is well conserved in both eukaryotic and prokaryotic organisms. Many Clp proteins ar