TY - JOUR A1 - Eulalio, Ana A1 - Fröhlich, Kathrin S. A1 - Mano, Miguel A1 - Giacca, Mauro A1 - Vogel, Jörg T1 - A Candidate Approach Implicates the Secreted Salmonella Effector Protein SpvB in P-Body Disassembly N2 - P-bodies are dynamic aggregates of RNA and proteins involved in several post-transcriptional regulation processes. Pbodies have been shown to play important roles in regulating viral infection, whereas their interplay with bacterial pathogens, specifically intracellular bacteria that extensively manipulate host cell pathways, remains unknown. Here, we report that Salmonella infection induces P-body disassembly in a cell type-specific manner, and independently of previously characterized pathways such as inhibition of host cell RNA synthesis or microRNA-mediated gene silencing. We show that the Salmonella-induced P-body disassembly depends on the activation of the SPI-2 encoded type 3 secretion system, and that the secreted effector protein SpvB plays a major role in this process. P-body disruption is also induced by the related pathogen, Shigella flexneri, arguing that this might be a new mechanism by which intracellular bacterial pathogens subvert host cell function. KW - Salmonella KW - RNS Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68928 ER - TY - JOUR A1 - Fröhlich, Kathrin S. A1 - Papenfort, Kai A1 - Berger, Allison A. A1 - Vogel, Jörg T1 - A conserved RpoS-dependent small RNA controls the synthesis of major porin OmpD JF - Nucleic Acids Research N2 - A remarkable feature of many small non-coding RNAs (sRNAs) of Escherichia coli and Salmonella is their accumulation in the stationary phase of bacterial growth. Several stress response regulators and sigma factors have been reported to direct the transcription of stationary phase-specific sRNAs, but a widely conserved sRNA gene that is controlled by the major stationary phase and stress sigma factor, Sigma(S) (RpoS), has remained elusive. We have studied in Salmonella the conserved SdsR sRNA, previously known as RyeB, one of the most abundant stationary phase-specific sRNAs in E. coli. Alignments of the sdsR promoter region and genetic analysis strongly suggest that this sRNA gene is selectively transcribed by Sigma(S). We show that SdsR down-regulates the synthesis of the major Salmonella porin OmpD by Hfq-dependent base pairing; SdsR thus represents the fourth sRNA to regulate this major outer membrane porin. Similar to the InvR, MicC and RybB sRNAs, SdsR recognizes the ompD mRNA in the coding sequence, suggesting that this mRNA may be primarily targeted downstream of the start codon. The SdsR-binding site in ompD was localized by 3'-RACE, an experimental approach that promises to be of use in predicting other sRNA-target interactions in bacteria. KW - shock sigma factor KW - general stress response KW - down regulation KW - stationary phase KW - salmonella enterica KW - messenger RNA KW - escherichia coli KW - enterica serovar typhimurium KW - outer-membrane proteins KW - small noncoding RNAs Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-134230 VL - 40 IS - 8 ER - TY - JOUR A1 - Dimastrogiovanni, Daniela A1 - Fröhlich, Kathrin S. A1 - Bandyra, Katarzyna J. A1 - Bruce, Heather A. A1 - Hohensee, Susann A1 - Vogel, Jörg A1 - Luisi, Ben F. T1 - Recognition of the small regulatory RNA RydC by the bacterial Hfq protein JF - eLife N2 - Bacterial small RNAs (sRNAs) are key elements of regulatory networks that modulate gene expression. The sRNA RydC of Salmonella sp. and Escherichia coli is an example of this class of riboregulators. Like many other sRNAs, RydC bears a 'seed' region that recognises specific transcripts through base-pairing, and its activities are facilitated by the RNA chaperone Hfq. The crystal structure of RydC in complex with E. coli Hfq at 3.48 angstrom resolution illuminates how the protein interacts with and presents the sRNA for target recognition. Consolidating the protein-RNA complex is a host of distributed interactions mediated by the natively unstructured termini of Hfq. Based on the structure and other data, we propose a model for a dynamic effector complex comprising Hfq, small RNA, and the cognate mRNA target. KW - Hfq KW - small RNA KW - natively unstructured protein KW - protein-RNA recognition KW - gene regulation KW - Escherichia coli-Hfq KW - SM-like protein KW - messenger-RNA KW - chaperone Hfq KW - target recognition KW - noncoding RNAs KW - interaction surfaces KW - crystal-structures KW - soluble-RNAs KW - C-Terminus Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-114191 SN - 2050-084X VL - 3 IS - e05375 ER - TY - JOUR A1 - Fröhlich, Kathrin S. A1 - Haneke, Katharina A1 - Papenfort, Kai A1 - Vogel, Jörg T1 - The target spectrum of SdsR small RNA in Salmonella JF - Nucleic Acids Research N2 - Model enteric bacteria such as Escherichia coli and Salmonella enterica express hundreds of small non-coding RNAs (sRNAs), targets for most of which are yet unknown. Some sRNAs are remarkably well conserved, indicating that they serve cellular functions that go beyond the necessities of a single species. One of these ‘core sRNAs’ of largely unknown function is the abundant ∼100-nucleotide SdsR sRNA which is transcribed by the general stress σ-factor, σ\(^{S}\) and accumulates in stationary phase. In Salmonella, SdsR was known to inhibit the synthesis of the species-specific porin, OmpD. However, sdsR genes are present in almost all enterobacterial genomes, suggesting that additional, conserved targets of this sRNA must exist. Here, we have combined SdsR pulse-expression with whole genome transcriptomics to discover 20 previously unknown candidate targets of SdsR which include mRNAs coding for physiologically important regulators such as the carbon utilization regulator, CRP, the nucleoid-associated chaperone, StpA and the antibiotic resistance transporter, TolC. Processing of SdsR by RNase E results in two cellular SdsR variants with distinct target spectra. While the overall physiological role of this orphan core sRNA remains to be fully understood, the new SdsR targets present valuable leads to determine sRNA functions in resting bacteria. KW - sRNA KW - Salmonella enterica KW - SdsR Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175365 VL - 44 IS - 21 ER -