Temperature‐induced regulation of RpoS by a small RNA in <i>Borrelia burgdorferi</i>

Lybecker, Meghan; Samuels, D. Scott

doi:10.1111/j.1365-2958.2007.05716.x

Cited by 152 publications

(227 citation statements)

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“…Bioinformatic approaches to identify the small RNA molecule(s) that could titrate the effects of CsrA have not yielded sequences with significant homology to CsrB/CsrC, while a homolog of small RNA molecule DsrA Bb has been determined to mediate the temperature-induced regulation of RpoS (50). We, therefore, decided to initially determine the levels of CsrA in various borrelial isolates to establish if CsrA does indeed play a role in the pathophysiological response of B. burgdorferi.…”

Section: Discussionmentioning

confidence: 99%

“…The temperature-induced reciprocal regulation of OspC and OspA controlled by RpoS has been recently shown to be mediated by a small, noncoding RNA, DsrA Bb , which has structural features that extensively base-pair with the upstream region of rpoS transcript (50). It was also elegantly demonstrated that B. burgdorferi mutants lacking DsrA Bb were unable to upregulate RpoS and OspC in response to temperature, while their regulation was unaffected in response to pH and cell density.…”

Section: Discussionmentioning

confidence: 99%

“…It was also elegantly demonstrated that B. burgdorferi mutants lacking DsrA Bb were unable to upregulate RpoS and OspC in response to temperature, while their regulation was unaffected in response to pH and cell density. Moreover, the regulation of RpoS was shown to be at the posttranscriptional level where the binding of DsrA Bb to the upstream region of the rpoS transcripts results in destabilization of a stable secondary structure, resulting in increased translational efficiency (50). While we have not delineated the differential roles of temperature, pH, or conditions of the medium associated with increased cell density in the levels of CsrA Bb , there are several features of DsrA Bb -RpoS interactions that are akin to the other small noncoding RNA-dependent gene regulation processes such as that observed with CsrA/CsrB/CsrC.…”

Section: Discussionmentioning

confidence: 99%

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Overexpression of CsrA (BB0184) Alters the Morphology and Antigen Profiles ofBorrelia burgdorferi

et al. 2009

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Overexpression of CsrA (BB0184) Alters the Morphology and Antigen Profiles ofBorrelia burgdorferi

et al. 2009

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“…A similar regulatory mechanism has been proposed for the action of DsrA RNA in E. coli (Majdalani et al, 1998) and Borrelia burgdorferi (Lybecker & Samuels, 2007) in order to facilitate rpoS mRNA translation. It has also been proposed for RNAIII in Staphylococcus aureus (Morfeldt et al, 1995) that acts on hla mRNA, encoding toxin, and also RyhB RNA that promotes the translation of shiA mRNA, encoding shikimate permease (Prévost et al, 2007).…”

Section: Determination Of the Termination Of Transcription Of A-furmentioning

confidence: 99%

“…It has also been proposed for RNAIII in Staphylococcus aureus (Morfeldt et al, 1995) that acts on hla mRNA, encoding toxin, and also RyhB RNA that promotes the translation of shiA mRNA, encoding shikimate permease (Prévost et al, 2007). A similar mechanism of regulation has been described to facilitate rpoS mRNA translation in E. coli (Majdalani et al, 1998) and B. burgdorferi (Lybecker & Samuels, 2007), hla mRNA in S. aureus (Morfeldt et al, 1995) and shiA mRNA in E. coli (Prevost et al, 2007).…”

Section: Determination Of the Termination Of Transcription Of A-furmentioning

confidence: 99%

α-fur, an antisense RNA gene to fur in the extreme acidophile Acidithiobacillus ferrooxidans

2014

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A large non-coding RNA, termed a-Fur, of~1000 nt has been detected in the extreme acidophile Acidithiobacillus ferrooxidans encoded on the antisense strand to the iron-responsive master regulator fur (ferric uptake regulator) gene. A promoter for a-fur was predicted bioinformatically and validated using gene fusion experiments. The promoter is situated within the coding region and in the same sense as proB, potentially encoding a glutamate 5-kinase. The 39 termination site of the a-fur transcript was determined by 39 rapid amplification of cDNA ends to lie 7 nt downstream of the start of transcription of fur. Thus, a-fur is antisense to the complete coding region of fur, including its predicted ribosome-binding site. The genetic context of a-fur is conserved in several members of the genus Acidithiobacillus but not in all acidophiles, indicating that it is monophyletic but not niche specific. It is hypothesized that a-Fur regulates the cellular level of Fur. This is the fourth example of an antisense RNA to fur, although it is the first in an extreme acidophile, and underscores the growing importance of cis-encoded non-coding RNAs as potential regulators involved in the microbial iron-responsive stimulon. INTRODUCTIONIron is an important micronutrient for micro-organisms because it is used as a cofactor for a large number of enzymes and electron transport proteins (Williams, 2012). However, it can also catalyse the Fenton reaction, generating hydroxyl radicals ( ? OH) that can damage many biological components, including DNA and proteins (Imlay, 2008;Cornelis et al., 2011). It is found at levels of~10 218 M (Andrews et al., 2003;Williams, 2012) in neutral, aerobic environments, which is far below the minimum requirement for bacterial growth (10 27 M) (Andrews et al., 2003). Consequently, micro-organisms have evolved complex systems for the uptake of iron, and have developed tight intracellular homeostatic controls to balance iron uptake and storage to avoid possible oxidative stress (Imlay, 2008;Cornelis et al., 2011). In many bacteria, this regulation is achieved by the action of the Fur (ferric uptake regulator) protein.In iron-rich conditions, Fur binds Fe 2+ (Mills & Marletta, 2005) and functions as a transcriptional repressor by binding to Fur boxes near promoter sequences blocking the entry of RNA polymerase, thus inhibiting initiation of RNA transcription. Genes regulated in this manner include those involved in the biosynthesis of siderophores and iron uptake (Friedman & O'Brian, 2003; Quatrini et al., 2007;Gao et al., 2008;Butcher et al., 2012), genes encoding small RNAs such as fsrA and ryhB (Smaldone et al., 2012;Massé & Gottesman, 2002;Salvail & Massé, 2012), and many other genes involved in iron homeostasis (reviewed by Salvail & Massé, 2012). Under iron-limiting conditions, Fur no longer binds Fe 2+ , reducing its affinity for Fur boxes and thus allowing transcription to proceed (Baichoo et al., 2002;Ochsner et al., 2002;Butcher et al., 2012). In the case of the siderophore and iron-uptake genes, t...

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Small Regulatory RNAs in Bacteria

Delihas

2016

Encyclopedia of Life Sciences

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Intergenic regions of bacteria contain small regulatory ribonucleic acid (sRNA) genes whose transcripts control expression of distal genes. These transcripts, referred to as sRNAs, primarily act at the level of translation where they bind messenger ribonucleic acids (mRNAs) and inhibit or activate a target mRNA. Base pairing with mRNAs is generally imperfect and can include noncanonical base pairs. The RNA chaperone protein Hfq is involved in many RNA/RNA interactions and ribonucleases RNase E and RNase III have been implicated in destabilisation of target mRNAs. Many sRNAs can inhibit multiple mRNAs; however, some sRNAs bind proteins and can regulate transcription or translation indirectly. Some act like ‘sponges’ that bind and sequester proteins involved in global gene regulation. Many sRNA genes are activated by environmental stress factors, and the sRNA genes have complex upstream regulatory sites. Further insight into broad functions of sRNAs comes from human host cells infected by pathogenic bacteria, which reveals a role of sRNA in both virulence and response in human host cell molecular functions, for example changes in long noncoding RNAs and microRNAs. Bacterial regulatory RNAs are proving to be remarkable factors in both cell physiology and bacterial pathogenesis and these RNAs have opened a new world in molecular biology. Key Concepts Small regulatory RNA genes have been found in most bacterial species. sRNA transcripts are generally less than 200 nt. sRNAs can control gene expression at the level of translation or transcription. sRNAs respond to environmental or internal stress conditions. sRNAs generally form small and imperfect RNA/RNA base pairing with target mRNA; noncanonical base pairs can also be present. sRNAs can inhibit translational and/or induce degradation of target mRNA. Many sRNAs regulate multiple target mRNAs. sRNAs can indirectly regulate the expression of global genes, some by binding proteins that control gene expression. sRNAs can play a major role in bacterial pathogenicity and influence eukaryotic host molecular functions such as levels of host cell microRNA and long noncoding RNA.

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Temperature‐induced regulation of RpoS by a small RNA in Borrelia burgdorferi

Cited by 152 publications

References 85 publications

Overexpression of CsrA (BB0184) Alters the Morphology and Antigen Profiles ofBorrelia burgdorferi

Overexpression of CsrA (BB0184) Alters the Morphology and Antigen Profiles ofBorrelia burgdorferi

α-fur, an antisense RNA gene to fur in the extreme acidophile Acidithiobacillus ferrooxidans

Small Regulatory RNAs in Bacteria

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