Lmo0688 (GmaR) regulon at room temperature

Microarray analyses comparing the transcriptional profile of wild-type EGDe relative to ∆lmo0688 (L. monocytogenes) during standing growth at RT in BHI broth. These analyses revealed that Lmo0688 is required for expression of flagellar motility genes during growth at RT. In this study, we identify an additional component of the molecular circuitry governing temperature-dependent flagellar gene expression. At low temperatures (30˚C and below), MogR repression activity is specifically inhibited by an anti-repressor, GmaR. We demonstrate that GmaR forms a stable complex with MogR, preventing MogR from binding its DNA target sites. GmaR anti-repression activity is temperature-dependent due to DegU-dependent transcriptional activation of gmaR at low temperatures. Thus, GmaR production represents the first committed step for flagella production in L. monocytogenes. Interestingly, GmaR also functions as a glycosyltransferase exhibiting O-linked N-acetylglucosamine transferase (OGT) activity for flagellin (FlaA). GmaR is the first OGT to be identified and characterized in prokaryotes. Unlike the well-characterized, highly conserved OGT regulatory protein in eukaryotes, the catalytic activity of GmaR is functionally separable from its anti-repression function. Keywords: EGDe vs ∆688, Temperature, Growth condition Oligonucleotide spotted arrays obtained from the Pathogen Functional Genomic Resource Center at TIGR were used for competitive hybridization studies comparing the transcriptional profile of wild-type EGDe to ∆lmo0688 (L. monocytogenes). Two technical replicates with associated dye swaps was performed for each growth condition.