Synergies between RNA degradation and trans-translation in Streptococcus pneumoniae: cross regulation and co-transcription of RNase R and SmpB

BMC Microbiology

Research Article

Susana Domingues¹  Sandra C Viegas¹  Cecília M Arraiano¹  Ricardo N Moreira¹  Mónica Amblar² 

[1] Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal;Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, and CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, 28220, Majadahonda, Madrid, Spain;

关键词: RNA turnover;    Post-transcriptional control;    Quality control;    Transcriptional unit;    Non-stop RNA decay;   

DOI  :  10.1186/1471-2180-12-268

 received in 2012-07-19, accepted in 2012-10-31,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundRibonuclease R (RNase R) is an exoribonuclease that recognizes and degrades a wide range of RNA molecules. It is a stress-induced protein shown to be important for the establishment of virulence in several pathogenic bacteria. RNase R has also been implicated in the trans-translation process. Transfer-messenger RNA (tmRNA/SsrA RNA) and SmpB are the main effectors of trans-translation, an RNA and protein quality control system that resolves challenges associated with stalled ribosomes on non-stop mRNAs. Trans-translation has also been associated with deficiencies in stress-response mechanisms and pathogenicity.ResultsIn this work we study the expression of RNase R in the human pathogen Streptococcus pneumoniae and analyse the interplay of this enzyme with the main components of the trans-translation machinery (SmpB and tmRNA/SsrA). We show that RNase R is induced after a 37°C to 15°C temperature downshift and that its levels are dependent on SmpB. On the other hand, our results revealed a strong accumulation of the smpB transcript in the absence of RNase R at 15°C. Transcriptional analysis of the S. pneumoniae rnr gene demonstrated that it is co-transcribed with the flanking genes, secG and smpB. Transcription of these genes is driven from a promoter upstream of secG and the transcript is processed to yield mature independent mRNAs. This genetic organization seems to be a common feature of Gram positive bacteria, and the biological significance of this gene cluster is further discussed.ConclusionsThis study unravels an additional contribution of RNase R to the trans-translation system by demonstrating that smpB is regulated by this exoribonuclease. RNase R in turn, is shown to be under the control of SmpB. These proteins are therefore mutually dependent and cross-regulated. The data presented here shed light on the interactions between RNase R, trans-translation and cold-shock response in an important human pathogen.

【 授权许可】

Unknown   
© Moreira et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.