Concerted Actions of a Thermo-labile Regulator and a Unique Intergenic RNA Thermosensor Control Yersinia Virulence

Böhme, Katja; Steinmann, Rebekka; Kortmann, Jens; Seekircher, Stephanie; Heroven, Ann Kathrin; Berger, Evelin; Pisano, Fabrizio; Thiermann, Tanja; Wolf‐Watz, Hans; Narberhaus, Franz; Dersch, Petra

doi:10.1371/journal.ppat.1002518

Cited by 149 publications

(286 citation statements)

References 84 publications

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“…Several human pathogenic bacteria produce virulence-associated traits only under conditions of infection, and in various instances temperature has been shown to play a major role in the regulation of their expression (8)(9)(10). In these cases, the production of virulence determinants is completely abrogated at environmental temperatures (30°C or lower), whereas the genes encoding these factors are fully expressed at 37°C.…”

Section: Significancementioning

confidence: 99%

“…In these cases, the production of virulence determinants is completely abrogated at environmental temperatures (30°C or lower), whereas the genes encoding these factors are fully expressed at 37°C. In many organisms, the modulation of the expression of genes encoding virulenceassociated traits is achieved by RNA structures present in the 5′ untranslated region (UTR) of genes encoding key transcriptional regulators (10,11). Recently, it was reported that P. aeruginosa genes encoding virulence factors regulated by QS were induced at 37°C, the human body temperature (12); however, the molecular mechanism for this thermoregulation has not yet been determined.…”

Section: Significancementioning

confidence: 99%

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Regulation of Pseudomonas aeruginosa virulence factors by two novel RNA thermometers

Grosso-Becerra

Croda-García

Merino

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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In a number of bacterial pathogens, the production of virulence factors is induced at 37°C; this effect is often regulated by mRNA structures formed in the 5′ untranslated region (UTR) that block translation initiation of genes at environmental temperatures. At 37°C, the RNA structures become unstable and ribosomes gain access to their binding sites in the mRNAs. Pseudomonas aeruginosa is an important opportunistic pathogen and the expression of many of its virulence-associated traits is regulated by the quorum-sensing (QS) response, but the effect of temperature on virulence-factor expression is not well-understood. The aim of this work is the characterization of the molecular mechanism involved in thermoregulation of QS-dependent virulence-factor production. We demonstrate that traits that are dependent on the QS transcriptional regulator RhlR have a higher expression at 37°C, correlating with a higher RhlR concentration as measured by Western blot. We also determined, using gene fusions and point mutations, that RhlR thermoregulation is a posttranscriptional effect dependent on an RNA thermometer of the ROSE (Repression Of heat-Shock gene Expression) family. This RNA element regulates the expression of the rhlAB operon, involved in rhamnolipid production, and of the downstream rhlR gene. We also identified a second functional thermometer in the 5′ UTR of the lasI gene. We confirmed that these RNA thermometers are the main mechanism of thermoregulation of QS-dependent gene expression in P. aeruginosa using quantitative real-time PCR. This is the first description, to our knowledge, of a ROSE element regulating the expression of virulence traits and of an RNA thermometer controlling multiple genes in an operon through a polar effect.RNA thermometers | bacterial virulence | gene regulation | polarity | quorum sensing A free-living γ-proteobacterium, Pseudomonas aeruginosa is one of the most clinically important opportunistic pathogens. It is responsible for acute infections in immune-compromised individuals and is the primary cause of death in patients with cystic fibrosis (1). The wide pathogenic capacity of this bacterium depends on its ability to produce and secrete multiple virulence factors that are regulated at the transcriptional level by the quorum-sensing (QS) response (2). Several mechanistic details of this intricate regulatory network remain to be elucidated at the molecular level.The QS response is mediated by the bacterial production of acyl-homoserine lactones (autoinducers) that act as signal molecules interacting with transcriptional regulators of the LuxR family. In P. aeruginosa, Las and Rhl QS regulation is arranged in a hierarchical cascade. LasR interacts with 3-oxo-dodecanoylhomoserine lactone (3O-C12-HSL) produced by the LasI enzyme, and activates the transcription of several genes encoding virulence factors and also of rhlR, lasI, and rhlI; rhlR encodes the second QS transcriptional regulator, whereas the product of the rhlI gene is the enzyme that produces butanoyl-homoserine lactone (C...

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Section: Significancementioning

confidence: 99%

Section: Significancementioning

confidence: 99%

Regulation of Pseudomonas aeruginosa virulence factors by two novel RNA thermometers

Grosso-Becerra

Croda-García

Merino

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…Y. pseudotuberculosis is a foodborne pathogen closely related to Y. pestis and causes enteritis, diarrhea, and mesenteric lymphadenitis in animals and humans. Its metabolism and virulence are strictly temperature controlled by various posttranscriptional mechanisms (6,26). An intercistronic RNAT is present upstream of low calcium response gene F (lcrF) coding for the master regulator of Yersinia virulence (6).…”

mentioning

confidence: 99%

Temperature-responsive in vitro RNA structurome of Yersinia pseudotuberculosis

Righetti

Nuss

Twittenhoff

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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136

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RNA structures are fundamentally important for RNA function. Dynamic, condition-dependent structural changes are able to modulate gene expression as shown for riboswitches and RNA thermometers. By parallel analysis of RNA structures, we mapped the RNA structurome of Yersinia pseudotuberculosis at three different temperatures. This human pathogen is exquisitely responsive to host body temperature (37°C), which induces a major metabolic transition. Our analysis profiles the structure of more than 1,750 RNAs at 25°C, 37°C, and 42°C. Average mRNAs tend to be unstructured around the ribosome binding site. We searched for 5′-UTRs that are folded at low temperature and identified novel thermoresponsive RNA structures from diverse gene categories. The regulatory potential of 16 candidates was validated. In summary, we present a dynamic bacterial RNA structurome and find that the expression of virulence-relevant functions in Y. pseudotuberculosis and reprogramming of its metabolism in response to temperature is associated with a restructuring of numerous mRNAs.RNA structure | RNA thermometer | temperature | virulence | translational control R NA structures play a pivotal role in the function of noncoding RNAs (ncRNAs) comprised of rRNAs, tRNAs, and small regulatory RNAs (sRNAs) and in the expression of proteincoding mRNAs. Structured segments affect the entire RNA life cycle from transcription, maturation, and translation to degradation and determine the specificity of interactions with other RNAs, proteins, or ligands. Although some RNAs, such as ribozymes and rRNAs, adopt rather stable secondary and tertiary structures, many regulatory RNA elements are dynamic and undergo structural rearrangements in the physiological temperature range. Well-known examples are metabolite-sensing riboswitches (1) and temperaturesensing RNA thermometers (RNATs) (2). Bacterial RNATs are usually located in the 5′-UTR or the intercistronic region (ICR) of an mRNA and differentially control translation of the downstream ORF in response to temperature (3). Typically, an RNAT folds into a structure that occludes the ribosome binding site (RBS). A temperature upshift liberates the RBS and allows the ribosome to bind and initiate translation. Structurally diverse RNATs are located upstream of many bacterial heat shock and virulence genes. Thermosensitive RNA structures playing a role in infection and host adaptation processes have been documented in Listeria monocytogenes (4), Yersinia pestis (5), Yersinia pseudotuberculosis (6), Leptospira interrogans (7), Shigella dysenteriae (8), Neisseria meningitidis (9), Pseudomonas aeruginosa (10), and Vibrio cholerae (11).In contrast to ligand-binding riboswitches, RNATs show poor, if any, conservation in sequence and structure. This diversity has hampered the in silico identification of novel RNATs, but recently developed genome-wide RNA structure-probing approaches offer new opportunities (12). Global structure probing maps the structures of the entire pool of expressed RNA molecules and provides a sna...

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“…Surprisingly, so far only one RNAT has been identified and characterized in Y. pseudotuberculosis, the lcrF RNAT located in the intergenic region of the yscWlcrF operon [42] [44]. In addition to translation, the transcription of many RNAT-controlled genes (e.g.…”

Section: Rna Thermometers (Rnats)mentioning

confidence: 99%