@article{BelairBaudChabasetal.2011, author = {Belair, C{\´e}dric and Baud, Jessica and Chabas, Sandrine and Sharma, Cynthia M and Vogel, J{\"o}rg and Staedel, Cathy and Darfeuille, Fabien}, title = {Helicobacter pylori interferes with an embryonic stem cell micro RNA cluster to block cell cycle progression}, series = {Silence : a Journal of RNA regulation}, volume = {2}, journal = {Silence : a Journal of RNA regulation}, number = {7}, doi = {10.1186/1758-907X-2-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-140438}, pages = {1-16}, year = {2011}, abstract = {Background MicroRNAs, post-transcriptional regulators of eukaryotic gene expression, are implicated in host defense against pathogens. Viruses and bacteria have evolved strategies that suppress microRNA functions, resulting in a sustainable infection. In this work we report that Helicobacter pylori, a human stomach-colonizing bacterium responsible for severe gastric inflammatory diseases and gastric cancers, downregulates an embryonic stem cell microRNA cluster in proliferating gastric epithelial cells to achieve cell cycle arrest. Results Using a deep sequencing approach in the AGS cell line, a widely used cell culture model to recapitulate early events of H. pylori infection of gastric mucosa, we reveal that hsa-miR-372 is the most abundant microRNA expressed in this cell line, where, together with hsa-miR-373, it promotes cell proliferation by silencing large tumor suppressor homolog 2 (LATS2) gene expression. Shortly after H. pylori infection, miR-372 and miR-373 synthesis is highly inhibited, leading to the post-transcriptional release of LATS2 expression and thus, to a cell cycle arrest at the G1/S transition. This downregulation of a specific cell-cycle-regulating microRNA is dependent on the translocation of the bacterial effector CagA into the host cells, a mechanism highly associated with the development of severe atrophic gastritis and intestinal-type gastric carcinoma. Conclusions These data constitute a novel example of host-pathogen interplay involving microRNAs, and unveil the couple LATS2/miR-372 and miR-373 as an unexpected mechanism in infection-induced cell cycle arrest in proliferating gastric cells, which may be relevant in inhibition of gastric epithelium renewal, a major host defense mechanism against bacterial infections.}, language = {en} } @article{EulalioFroehlichManoetal.2011, author = {Eulalio, Ana and Fr{\"o}hlich, Kathrin S. and Mano, Miguel and Giacca, Mauro and Vogel, J{\"o}rg}, title = {A Candidate Approach Implicates the Secreted Salmonella Effector Protein SpvB in P-Body Disassembly}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-68928}, year = {2011}, abstract = {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.}, subject = {Salmonella}, language = {en} } @article{SchmidtkeFindeissSharmaetal.2011, author = {Schmidtke, Cornelius and Findeiß, Sven and Sharma, Cynthia M. and Kuhfuss, Juliane and Hoffmann, Steve and Vogel, J{\"o}rg and Stadler, Peter F. and Bonas, Ulla}, title = {Genome-wide transcriptome analysis of the plant pathogen Xanthomonas identifies sRNAs with putative virulence functions}, series = {Nucleic Acids Research}, volume = {40}, journal = {Nucleic Acids Research}, number = {5}, doi = {10.1093/nar/gkr904}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131781}, pages = {2020 -- 2031}, year = {2011}, abstract = {The Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) is an important model to elucidate the mechanisms involved in the interaction with the host. To gain insight into the transcriptome of the Xcv strain 85-10, we took a differential RNA sequencing (dRNA-seq) approach. Using a novel method to automatically generate comprehensive transcription start site (TSS) maps we report 1421 putative TSSs in the Xcv genome. Genes in Xcv exhibit a poorly conserved -10 promoter element and no consensus Shine-Dalgarno sequence. Moreover, 14\% of all mRNAs are leaderless and 13\% of them have unusually long 5'-UTRs. Northern blot analyses confirmed 16 intergenic small RNAs and seven cis-encoded antisense RNAs in Xcv. Expression of eight intergenic transcripts was controlled by HrpG and HrpX, key regulators of the Xcv type III secretion system. More detailed characterization identified sX12 as a small RNA that controls virulence of Xcv by affecting the interaction of the pathogen and its host plants. The transcriptional landscape of Xcv is unexpectedly complex, featuring abundant antisense transcripts, alternative TSSs and clade-specific small RNAs.}, language = {en} }