Identification of differentially expressed small non-protein-coding RNAs in Staphylococcus aureus displaying both the normal and the small-colony variant phenotype
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The emerging interest in RNA research is due to the discovery that bacterial non-protein-coding RNAs (npcRNAs; often referred to as “non-coding RNAs”) are central regulatory molecules. While single npcRNAs have been described in Staphylococcus aureus, mostly based on computational-based approaches, experimental data on npcRNAs and their impact on the formation of different phenotypes of S. aureus are missing. Consequently, two specialized cDNA libraries were constructed from total RNA collected from different growth phases of an isogenic clinical strain pair of S. aureus displaying both the normal and the small-colony variant phenotype. Overall, 142 candidates for novel npcRNAs were identified and their expression analyzed by Northern blot assays. Of these, the presence of 18 novel npcRNAs in S. aureus was experimentally confirmed. In fact, growth phase-specific regulation was detected for almost all of the novel npcRNAs, with different npcRNA expression patterns detectable for both phenotypes. Of particular interest, S. aureus phenotype-specific expression of four novel npcRNAs was documented. Thus, the presence of differentially expressed npcRNAs in S. aureus may help to understand the phenotypic variation and its associated pathogenicity.
KeywordsInfectiology Infection RNA Transcription
This work was supported in part by grants to CvE and KB from the Bundesministerium für Bildung und Forschung (BMBF), Germany (01KI07100 “Skin Staph” [Susceptibility and Resistance towards Infections] and PTJ-BIO/0313801B [Pathogenomic Plus Network]), by grants to KB (BE2546/1-1) and CvE (EI247/7-1) from the Deutsche Forschungsgemeinschaft as well as by grants to JB and TSR from the Nationales Genomforschungsnetz (NGFNII-EP 0313358A and NGFNIII 016S0808). LFA received a scholarship by the DAAD (A/05/55152).
The authors sincerely thank C. A. Raabe for support in computational analyses and helpful discussion. The authors are grateful to D. Kuhn for excellent technical assistance.
Conflict of interest statement
The authors declare no conflict of interest.
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