Small RNAs in streptococci

Rhun, Anaïs Le; Charpentier, Emmanuelle

doi:10.4161/rna.20104

Cited by 26 publications

(30 citation statements)

References 99 publications

(222 reference statements)

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“…The reduction of the costs and, with that, the accessibility of high-throughput RNA sequencing strategies now offer new possibilities. Although the knowledge about the role of sRNAs in LAB is still limited, genome-wide screens for sRNAs were recently performed on some species (637)(638)(639)(640)(641). These data are also the basis of the first functional studies with regard to the possible roles of these important regulatory molecules in stress responses (642).…”

Section: Discussionmentioning

confidence: 99%

Stress Physiology of Lactic Acid Bacteria

Papadimitriou

Alegría

Bron

et al. 2016

Microbiol Mol Biol Rev

515

404

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SUMMARYLactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g.,Lactococcus lactis), probiotic (e.g., severalLactobacillusspp.), and pathogenic (e.g.,EnterococcusandStreptococcusspp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.

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Section: Discussionmentioning

confidence: 99%

Stress Physiology of Lactic Acid Bacteria

Papadimitriou

Alegría

Bron

et al. 2016

Microbiol Mol Biol Rev

515

404

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“…Transcriptional control of GAS virulence factor production has been investigated in detail, and several specific and global gene regulators have been identified (16)(17)(18). However, regulatory control of virulence factor production is more complex and includes the interplay of several regulatory circuits (19) and a multilayer control at the posttranscriptional level (20)(21)(22)(23). For example, the mRNAs for streptolysin S (encoded by sagA) and streptodornase (encoded by sda) are greatly stabilized during entry into the stationary phase.…”

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confidence: 99%

Multiple Roles of RNase Y in Streptococcus pyogenes mRNA Processing and Degradation

et al. 2013

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Control over mRNA stability is an essential part of gene regulation that involves both endo-and exoribonucleases. RNase Y is a recently identified endoribonuclease in Gram-positive bacteria, and an RNase Y ortholog has been identified in Streptococcus pyogenes (group A streptococcus [GAS]). In this study, we used microarray and Northern blot analyses to determine the S. pyogenes mRNA half-life of the transcriptome and to understand the role of RNase Y in global mRNA degradation and processing. We demonstrated that S. pyogenes has an unusually high mRNA turnover rate, with median and mean half-lives of 0.88 min and 1.26 min, respectively. A mutation of the RNase Y-encoding gene (rny) led to a 2-fold increase in overall mRNA stability. RNase Y was also found to play a significant role in the mRNA processing of virulence-associated genes as well as in the rapid degradation of rnpB read-through transcripts. From these results, we conclude that RNase Y is a pleiotropic regulator required for mRNA stability, mRNA processing, and removal of read-through transcripts in S. pyogenes. RNA degradation is a strictly regulated process that involves both endo-and exoribonucleases (1). In prokaryotes, mRNA degradation is initiated by endonucleolytic cleavage and followed by exonuclease digestion (2-4). The first step is relatively slow and rate limiting, while the second step proceeds rapidly (1). In Escherichia coli, RNase E functions as the major endoribonuclease that initiates the bulk of mRNA degradation (5). Although RNase E is absent in Bacillus subtilis, the recently identified RNase Y is considered its functional analog (6). RNase E and RNase Y do not share sequence homology but are strikingly similar in function (7,8). Both RNases are membrane-bound proteins that interact with other components to form a complex called the RNA degradosome (7, 9). These components include other RNases, an RNA helicase, and two glycolytic enzymes (10, 11). Both RNase Y and RNase E prefer 5= monophosphorylated RNA substrates with downstream secondary structures (6, 12). The depletion of B. subtilis RNase Y results in the accumulation of about 550 mRNAs, including important transcriptional regulators for stress response and biofilm formation and metabolic operons for tryptophan biosynthesis and glycolytic enzymes (8). B. subtilis RNase Y also interacts with RNases J1 and III to control the abundance of total mRNAs (13). RNase Y of Staphylococcus aureus plays a major role in virulence gene regulation and is involved in the processing and stabilization of a global regulator system, SaePQRS (14). These observations suggest that RNase Y is the major endoribonuclease in mRNA degradation in B. subtilis and perhaps also in other Gram-positive pathogens, such as Streptococcus pyogenes.S. pyogenes (group A streptococcus [GAS]) causes a variety of human diseases ranging from mild local infections such as pharyngitis and impetigo to life-threatening systemic diseases such as toxic shock syndrome and necrotizing fasciitis (15). GAS infections often cau...

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“…Posttranscriptional mechanisms also have a variety of characteristics that make them particularly suited for highly dynamic genetic pathways like many of the major cellular adaptive responses. This includes the regulation of accessory genes and virulence factors in pathogens [29, 34, 54, 79, 86] as well as the corresponding immune responses of their infected hosts [5, 75, 105]. Posttranscriptional mechanisms offer a faster response time at a reduced energetic cost compared to most transcriptional mechanisms [34].…”

Section: Introductionmentioning

confidence: 99%