E. Gerhart H. Wagner

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BACKGROUND Small, untranslated RNA molecules were identified initially in bacteria, but examples can be found in all kingdoms of life. These RNAs carry out diverse functions, and many of them are regulators of gene expression. Genes encoding small, untranslated RNAs are difficult to detect experimentally or to predict by traditional sequence analysis(More)
This paper shows that the small RNA MicA (previously SraD) is an antisense regulator of ompA in Escherichia coli. MicA accumulates upon entry into stationary phase and down-regulates the level of ompA mRNA. Regulation of ompA (outer membrane protein A), previously attributed to Hfq/mRNA binding, is lost upon deletion of the micA gene, whereas overexpression(More)
More than 60 small RNAs (sRNA) have been identified in E. coli. The functions of the majority of these sRNAs are still unclear. For the few sRNAs characterized, expression and functional studies indicate that they act under stress conditions. Here, we describe a novel E. coli chromosome locus that is part of the SOS response to DNA damage. This locus(More)
The recently discovered prokaryotic CRISPR/Cas defence system provides immunity against viral infections and plasmid conjugation. It has been demonstrated that in Escherichia coli transcription of the Cascade genes (casABCDE) and to some extent the CRISPR array is repressed by heat-stable nucleoid-structuring (H-NS) protein, a global transcriptional(More)
Recent bioinformatics-aided searches have identified many new small RNAs (sRNAs) in the intergenic regions of the bacterium Escherichia coli. Here, a shot-gun cloning approach (RNomics) was used to generate cDNA libraries of small sized RNAs. Besides many of the known sRNAs, we found new species that were not predicted previously. The present work brings(More)
Small RNAs are ubiquitously present regulators in all kingdoms of life. Most bacterial and archaeal small RNAs (sRNAs) act by antisense mechanisms on multiple target mRNAs, thereby globally affecting essentially any conceivable trait-stress responses, adaptive metabolic changes, virulence etc. The sRNAs display many distinct mechanisms of action, most of(More)
Small noncoding RNAs have been discovered at a staggering rate in Escherichia coli and many other bacteria. Most of the sRNAs of known function regulate gene expression by binding to specific mRNAs or proteins. Given the scores of sRNAs of unknown function, the identification of their cellular targets has become urgent. Here, we review the diverse(More)
We previously reported on an SOS-induced toxin, TisB, in Escherichia coli and its regulation by the RNA antitoxin IstR-1. Here, we addressed the mode of action of TisB. By placing the tisB reading frame downstream of a controllable promoter on a plasmid, toxicity could be analysed in the absence of the global SOS response. Upon induction of TisB, cell(More)
Most antisense RNAs in bacteria inhibit translation by competing with ribosomes for translation initiation regions (TIRs) on nascent mRNA. We propose a mechanism by which an antisense RNA inhibits translation without binding directly to a TIR. The tisAB locus encodes an SOS-induced toxin, and IstR-1 is the antisense RNA that counteracts toxicity. We show(More)
The formation of heterochromatin at the centromeres in fission yeast depends on transcription of the outer repeats. These transcripts are processed into siRNAs that target homologous loci for heterochromatin formation. Here, high throughput sequencing of small RNA provides a comprehensive analysis of centromere-derived small RNAs. We found that the(More)