Insights into aureocin A70 regulation: participation of regulator AurR, alternative transcription factor sigma(B) and phage phi 11 regulator cI

摘要

Aureocin A70 is a four-component bacteriocin produced by Staphylococcus aureus A70. Its locus encompasses three transcriptional units coding for: (i) structural peptides (aurABCD), (ii) an ABC transporter (aurT) and (iii) the dedicated immunity protein and a putative transcriptional regulator (aurRI). The data provided here showed that AurR is an HTH-containing protein that reduces aureocin A70 production on solid medium, but not in broth. AurR seems to work similarly to LtnR and CylR(2), repressors of lantibiotics lacticin 3147 and cytolysin, respectively. At least two other factors play a role in aureocin A70 production: (i) the alternative sigma(B) factor, as sigma(B)-defective cells produce more bacteriocin than the restored sigma(B+) cells, and (ii) the phi 11 regulator cI, since a lysogenic strain for phi 11 exhibited a significant reduction in aureocin A70 production on solid medium when compared with the non-lysogenic isogenic strain. Full aeration and ROS generation abolished the effect of the phage regulators on aureocin A70 production. Interestingly, the phi 11 regulator cI seems to cooperate with AurR to abolish aureocin A70 production. This study therefore represents the first report showing that phage regulators may play a role in regulation of bacteriocin production. (C) 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.