lipases are well-studied, but few studies have examined the mechanisms of lipase expression regulation. As a global regulatory protein, PmrA controls the expression of multiple genes such as the Dot/Icm apparatus, eukaryotic-like proteins, and secreted effectors. In this study, the effect of PmrA on expression of the lipase lipA in PAO1 was investigated by knocking out or overexpressing , and . PmrA regulated the expression of at both the transcriptional and translational level although translation was the pivotal regulatory mechanism for expression. PmrA also regulated the expression of . Using gel mobility shift assay and double gene knock-out model, we showed that PmrA directly bound to the promoter sequence of to regulate expression. Translation of was activated by the PmrA/PmrB system via RsmA. Specifically, the Shine-Dalgarno (SD) sequence located at mRNA was overlapped through combination between RsmA and the AGAUGA sequence, subsequently blocking the 30S ribosomal subunit to the SD sequence, leading to translational inhibition of . Transcriptional repression of RsmY initiated translation of through negative translational regulation of . In conclusion, this study demonstrated that in PAO1, PmrA mainly regulated expression at a translational level to influence expression. RsmY primarily activated translation via negative translational regulation of .
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| http://dx.doi.org/10.3389/fmicb.2017.02690 | DOI Listing |
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