Regulation of Metalloprotease VvpE Production by Quorum-sensing System in Vibrio vulnificus

Expression of vvpE encoding a metalloprotease called VvpE is known to be positively regulated by the autoinducer-2-mediated quorum-sensing system (AI2-QSS). Recently, we found that both 35 and 45 kDa-VvpE, the authentic products of wpE, are produced within bacterial cells and thereafter secreted, and moreover, 35 kDa-VvpE is the major secreted form. In this study, we attempted to observe the effect of AI2-QSS on the production profile of VvpE. VvpE production was decreased along with the down-regulation of vvpE transcription by a mutation of luxS encoding an enzyme (LuxS) required for the synthesis of AI2 or of smcR encoding a master transcription activator (SmcR) of AI2-QSS. The decreased VvpE production was rescued by in trans complementation of wild-type luxS or smcR. However, the production profile of VvpE was not affected by mutation of luxS or smcR. These results indicate that AI2-QSS regulates VvpE production by controlling vvpE expression, but does not affect the production profile of VvpE.