A Proteomic Analysis Reveals Differential Regulation of the σS-Dependent yciGFE(katN) Locus by YncC and H-NS in Salmonella and Escherichia coli K-12

Abstract

The stationary phase sigma factor S (RpoS) controls a regulon required for general stress resistance of the closely related enterobacteria Salmonella and Escherichia coli. In eubacteria, transcription depends on a multisubunit RNA polymerase (RNAP) consisting of a catalytically active core enzyme (E) with a subunit structure ␣ 2 ␤␤', that associates with any one of several factors to form different holoenzyme (E) species. The subunit is required for specific promoter binding, and different factors direct RNAP to different classes of promoters, thereby modulating gene expression patterns (1). The RNA polymerase holoenzyme containing the 70 subunit is responsible for the transcription of most genes during exponential growth (1). When cells enter stationary phase or are under specific stress conditions during exponential growth, S , encoded by the rpoS gene, becomes more abundant, associates with the core enzyme, and directs the transcription of genes essential for the general stress response (1-3). In the closely related Enterobacteria Salmonella and Escherichia coli, S is required for stationary phase survival, stress resistance, and biofilm formation. It is also involved in the virulence of Salmonella enterica serovar Typhimurium (S. Typhimurium) (4). Transcriptome analyses in S. Typhimurium and E. coli K-12 have shown that rpoS controls more than 300 genes, 40% of which are of unknown function (3,5,6). A large fraction of S -controlled genes encode putative regulators and signal transducing factors, suggesting that S controls a complex network with regulatory cascades and signal input at levels downstream of S itself. We previously used a bank of S.Typhimurium mutants to identify S -regulated genes (7). One of these genes, the yncC gene (7), encoded a putative DNA binding protein of the GntR/FadR family of bacterial regulators (8 -10). To further investigate the function of the yncC gene, we decided to characterize the proteome of the Salmonella yncC mutant by the surface-enhanced laser desorption/ionization-time of flight (SELDI-TOF 1 ) ProteinChip technology.The SELDI-TOF method is based on the selective protein retention on a solid-phase chromatographic chip surface and successive analysis by simple laser desorption/ionization mass spectrometry (11). Because of its high-throughput nature and experimental simplicity, this technology has been widely used for protein profiling of tissues and biomarker discovery (11) and unpublished work from our laboratory reFrom the §Institut Pasteur, Unité de Gé né tique molé culaire, Dé partement de Microbiologie

Gallbladder Epithelium as a Niche for Chronic Salmonella Carriage

“…The yciE gene belongs to the operon yciGFE-katN, which is RpoS dependent, and it is upregulated in the presence of bile (36,(53)(54)(55). In addition, this gene was found to be 51-fold upregulated in biofilms on glass and cholesterol surfaces in a bile-containing medium (data not shown).…”

Transcriptional regulation by Ferric Uptake Regulator (Fur) in pathogenic bacteria

“…The Fur regulation of Mn 2+ transport is well-documented (Patzer and Hantke, 2001; Kehres et al, 2002; Guedon et al, 2003; Ikeda et al, 2005; Runyen-Janecky et al, 2006; Perry et al, 2012). Furthermore, because katN encodes a Mn-containing catalase and is activated by RpoS (Robbe-Saule et al, 2001) and repressed by H-NS (Beraud et al, 2010), it is likely that Fur is involved in katN expression in S. Typhimurium. Thus, the modulation of the intracellular Mn 2+ concentration will undoubtedly influence protection against ROS and likely virulence.…”

RpoS-regulated SEN1538 gene promotes resistance to stress and influences Salmonella enterica serovar enteritidis virulence

“…Previous reports on RpoS mutants have shown them to have defective swimming motility and phagocytic survival, be sensitive to stress, and be avirulent inside a host [14,42,43]. YciG, STM14_1829, and YmdF expression was shown to be regulated by RpoS [14][15][16]21,39,44,45]. A promoter specificity assay has also detected a RpoS binding site in the promoter region of these genes [15,21].…”

“…The KGG family proteins YciG, YmdF, and STM1513/ STM14_1829 are regulated by RpoS in S. Typhimurium and E. coli [14,16,39]. We investigated the role of RpoS in regulating SEN1538 in S. Enteritidis.…”