A global survey of small RNA interactors identifies KhpA and KhpB as major RNA-binding proteins in Fusobacterium nucleatum
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ABSTRACT:
ORGANISM(S): Fusobacterium nucleatum subsp. nucleatum ATCC 23726
PROVIDER: GSE246396 | GEO | 2024/02/01
REPOSITORIES: GEO
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Project description:The common oral microbe Fusobacterium nucleatum has recently gained attention when it was found to colonize tumors throughout the human body. Fusobacteria are also interesting in regard to bacterial RNA biology as these early-branching species encode many small noncoding RNAs (sRNAs) but lack homologs of the common RNA-binding proteins (RBPs) CsrA, Hfq and ProQ. Here, to search for alternate sRNA-associated RBPs in F. nucleatum, we performed a systematic mass spectrometry analysis of proteins that copurified with 19 different sRNAs. Our approach recovered a 6S RNA-RNA polymerase complex in this species and discovered high enrichment of the KH domain proteins KhpA and KhpB with almost any tested sRNA, including the σE-dependent sRNA FoxI, a regulator of several envelope proteins. KhpA/B act as a dimer to bind sRNAs with low micromolar affinity and influence the cellular stability of several of their targets. RNA-seq analysis and cell biological assays suggest that KhpA/B have several physiological functions, including a strong requirement for ethanolamine utilization. Our RBP search and discovery of KhpA/B as major RBPs in F. nucleatum are important first steps in identifying key players of post-transcriptional control at the root of the bacterial phylogenetic tree.
2024-02-08 | PXD046416 | Pride
Project description:The oral commensal Fusobacterium nucleatum can spread to extra-oral sites where it is associated with diverse pathologies including pre-term birth and cancer. Due to the evolutionary distance of F. nucleatum to other model bacteria, we lack a deeper understanding of RNA regulatory networks that allow this bacterium to adapt to its various niches. As a first step in that direction, we recently showed that F. nucleatum harbors a global stress response governed by the extracytoplasmic function sigma factor σE, which displays a striking functional conservation with Proteobacteria and includes a noncoding arm in the form of a regulatory small RNA (sRNA), FoxI. To search for putative additional σE-dependent sRNAs, we comprehensively mapped 5’- and 3’-ends of transcripts in the model strain ATCC 23726. This enabled the discovery of FoxJ, a ~156 nucleotide sRNA previously misannotated as the 5’ UTR of ylmH. FoxJ is tightly controlled by σE and activated by the same stress conditions as FoxI. Both sRNAs act as mRNA repressors of the abundant porin FomA, but FoxJ also regulates genes that are distinct from the target suite of FoxI. Moreover, FoxJ differs from most other σE-dependent sRNAs in that it also positively regulates genes at the post-transcriptional level. We provide preliminary evidence for a new mode of sRNA-mediated mRNA activation, which involves the targeting of intra-operonic terminators. Overall, our study provides an important resource through the comprehensive annotation of 5’- and 3’ UTRs in F. nucleatum and expands our understanding of the σE-response in this evolutionarily distant bacterium.
2024-02-08 | PXD047655 | Pride
Project description:The oral commensal Fusobacterium nucleatum can spread to extra-oral sites where it is associated with pathologies as diverse as pre-term birth or cancer. Due to the evolutionary distance of F. nucleatum to other model bacteria, we lack a deeper understanding of RNA regulatory networks that allow this bacterium to adapt to different environmental niches. As a first step in that direction, we recently showed that F. nucleatum harbors a global stress response governed by the extracytoplasmic function sigma factor σE, which displays a striking functional conservation with Proteobacteria and includes a noncoding arm in the form of a regulatory small RNA (sRNA), FoxI. To search for putative additional σE-dependent sRNAs, we comprehensively mapped 5’- and 3’-ends of transcripts in the model strain ATCC 23726. This enabled the discovery of FoxJ, a ~156 nucleotide sRNA previously misannotated as the 5’ UTR of ylmH. FoxJ is tightly controlled by σE and activated by the same stress conditions as FoxI. Both sRNAs act as mRNA repressors of the abundant porin FomA, but FoxJ also regulates genes that are distinct from the target suite of FoxI. Moreover, FoxJ differs from most other σE-dependent sRNAs in that it also positively regulates genes at the post-transcriptional level. We provide preliminary evidence for a new mode of sRNA-mediated mRNA activation, which involves the targeting of intra-operonic terminators. Overall, our study provides an important resource through the comprehensive annotation of 5’- and 3’ UTRs in F. nucleatum and expands our understanding of the σE-response in this evolutionarily distant bacterium.
2024-02-08 | GSE249955 | GEO
Project description:Legionella pneumophila is a gram-negative opportunistic human pathogen that infects and multiplies in a broad range of phagocytic protozoan and mammalian phagocytes. Based on the observation that small regulatory RNAs (sRNAs) play an important role in controlling virulence-related genes in several pathogenic bacteria, we attempted to test the hypothesis that sRNAs play a similar role in L. pneumophila. We used computational prediction followed by experimental verification to identify and characterize sRNAs encoded in the L. pneumophila genome. A 50-mer probe microarray was constructed to test the expression of predicted sRNAs in bacteria grown under a variety of conditions. This strategy successfully identified 22 expressed RNAs, out of which six were confirmed by northern blot and RACE. One of the identified sRNAs is highly expressed when the bacteria enter post exponential phase and computational prediction of its secondary structure reveals a striking similarity to the structure of 6S RNA, a widely distributed prokaryotic sRNA, known to regulate the activity of σ70-containing RNAP. A 70-mer probe microarray was used to identify genes affected by L. pneumophila 6S RNA in stationary phase. The 6S RNA encoded by the ssrS gene positively regulates expression of genes encoding type IVB secretion system effectors, stress response genes such as groES and recA as well as many genes with unknown or hypothetical functions. Deletion of 6S RNA significantly reduced L. pneumophila intracellular multiplication in both protist and mammalian host cells, but had no detectable effect on growth in rich media.
2010-01-01 | GSE19200 | GEO
Project description:Legionella pneumophila is a gram-negative opportunistic human pathogen that infects and multiplies in a broad range of phagocytic protozoan and mammalian phagocytes. Based on the observation that small regulatory RNAs (sRNAs) play an important role in controlling virulence-related genes in several pathogenic bacteria, we attempted to test the hypothesis that sRNAs play a similar role in L. pneumophila. We used computational prediction followed by experimental verification to identify and characterize sRNAs encoded in the L. pneumophila genome. A 50-mer probe microarray was constructed to test the expression of predicted sRNAs in bacteria grown under a variety of conditions. This strategy successfully identified 22 expressed RNAs, out of which six were confirmed by northern blot and RACE. One of the identified sRNAs is highly expressed when the bacteria enter post exponential phase and computational prediction of its secondary structure reveals a striking similarity to the structure of 6S RNA, a widely distributed prokaryotic sRNA, known to regulate the activity of σ70-containing RNAP. A 70-mer probe microarray was used to identify genes affected by L. pneumophila 6S RNA in stationary phase. The 6S RNA encoded by the ssrS gene positively regulates expression of genes encoding type IVB secretion system effectors, stress response genes such as groES and recA as well as many genes with unknown or hypothetical functions. Deletion of 6S RNA significantly reduced L. pneumophila intracellular multiplication in both protist and mammalian host cells, but had no detectable effect on growth in rich media.
2010-01-01 | GSE19196 | GEO
Project description:Legionella pneumophila is a gram-negative opportunistic human pathogen that infects and multiplies in a broad range of phagocytic protozoan and mammalian phagocytes. Based on the observation that small regulatory RNAs (sRNAs) play an important role in controlling virulence-related genes in several pathogenic bacteria, we attempted to test the hypothesis that sRNAs play a similar role in L. pneumophila. We used computational prediction followed by experimental verification to identify and characterize sRNAs encoded in the L. pneumophila genome. A 50-mer probe microarray was constructed to test the expression of predicted sRNAs in bacteria grown under a variety of conditions. This strategy successfully identified 22 expressed RNAs, out of which six were confirmed by northern blot and RACE. One of the identified sRNAs is highly expressed when the bacteria enter post exponential phase and computational prediction of its secondary structure reveals a striking similarity to the structure of 6S RNA, a widely distributed prokaryotic sRNA, known to regulate the activity of Ï70-containing RNAP. A 70-mer probe microarray was used to identify genes affected by L. pneumophila 6S RNA in stationary phase. The 6S RNA encoded by the ssrS gene positively regulates expression of genes encoding type IVB secretion system effectors, stress response genes such as groES and recA as well as many genes with unknown or hypothetical functions. Deletion of 6S RNA significantly reduced L. pneumophila intracellular multiplication in both protist and mammalian host cells, but had no detectable effect on growth in rich media. A microarray was designed for the detection of 101 predicted sRNAs by using OligiWiz version 2.1.3 (Nielsen et al., 2003, Wernersson & Nielsen, 2005). The prokaryotic setting was used to design 50-mers probes located, when possible, at the 3â end of the predicted genes. Probes for 10 negative controls, representing 10 genes of the L. pneumophila Paris plasmid, were also designed. Probes (Illumina) were dissolved in 50% DMSO to a final concentration of 30 uM and printed in triplicate on UltraGAPS coated glass slides (Corning) using a PerkinElmer SpotArray microarray printer. Fifteen micrograms of total RNA was labelled during cDNA synthesis using Superscript II reverse transcriptase (Invitrogen) and amino-allyl dUTP (Sigma). Bacterial genomic DNA was used as the reference channel on each slide to allow comparison of each time point and different samples (Talaat et al., 2002). Five micrograms of genomic DNA (gDNA) was labelled with amino-allyl dUTP by using Klenow fragment and random primers (Invitrogen) at 37 °C for 18 h. DNA was subsequently coupled to the succinimidyl ester fluorescent dye AlexaFluor 546 (for cDNA) or Alexa Fluor 647 (for gDNA) (Invitrogen) following manufacturerâs protocols. Hybridization and data acquisition were performed as previously described (Hovel-Miner et al., 2009).Very low density array, like the sRNA microarray used here, cannot be normalised with common procedure like total intensity or lowess. Local background was removed from spot signal intensity and the noise signal was estimated by recording the average signal intensity of 10 negative controls printed on the chip. Normalisation of signal intensity was carried out by calculating the fold increase over the noise signal value. Correlation of replicates using this normalisation procedure was ⥠0.95.
2010-06-24 | E-GEOD-19196 | biostudies-arrayexpress
Project description:Legionella pneumophila is a gram-negative opportunistic human pathogen that infects and multiplies in a broad range of phagocytic protozoan and mammalian phagocytes. Based on the observation that small regulatory RNAs (sRNAs) play an important role in controlling virulence-related genes in several pathogenic bacteria, we attempted to test the hypothesis that sRNAs play a similar role in L. pneumophila. We used computational prediction followed by experimental verification to identify and characterize sRNAs encoded in the L. pneumophila genome. A 50-mer probe microarray was constructed to test the expression of predicted sRNAs in bacteria grown under a variety of conditions. This strategy successfully identified 22 expressed RNAs, out of which six were confirmed by northern blot and RACE. One of the identified sRNAs is highly expressed when the bacteria enter post exponential phase and computational prediction of its secondary structure reveals a striking similarity to the structure of 6S RNA, a widely distributed prokaryotic sRNA, known to regulate the activity of Ï70-containing RNAP. A 70-mer probe microarray was used to identify genes affected by L. pneumophila 6S RNA in stationary phase. The 6S RNA encoded by the ssrS gene positively regulates expression of genes encoding type IVB secretion system effectors, stress response genes such as groES and recA as well as many genes with unknown or hypothetical functions. Deletion of 6S RNA significantly reduced L. pneumophila intracellular multiplication in both protist and mammalian host cells, but had no detectable effect on growth in rich media. The 70-mer microarray representing all annotated ORFs of L. pneumophila has been previously described (Charpentier et al., 2008). RNA was extracted from ssrS mutant strain and the wild-type strain grown to PE phase. gDNA was used as a reference channel on each slides. Labelling of samples, hybridization strategy and data acquisition were performed as described in the Methods section. Local background was removed from spot signal intensity and normalization was carried out by calculating the fraction over the total signal intensity in both channel as previously described (Faucher et al., 2006). Signal levels that were lower than background in experiments and controls were filtered out. A total of six cDNA to reference ratios were recorded for each time point. Statistical analysis between mutant and wild-type strain was performed using unpaired one-tailed studentâs t-test. Genes were considered as differentially expressed if they demonstrated a ratio to control value of ±2-fold with a p < 0.001.
2010-06-24 | E-GEOD-19200 | biostudies-arrayexpress
Project description:Methicillin resistant Staphylococcus aureus (MRSA) is an infectious pathogen that poses a significant threat to human health. MRSA is renowned for its ability to adapt to and even thrive in hostile environment within its host. By expressing a battery of virulence factors and toxins, MRSA is able to scavenge effectively essential nutrients and evade the immune system within the host. Post-transcriptional regulation by sRNAs contributes significantly to regulating the expression of virulence factors and toxins. However, the roles of the vast majority of sRNAs during host adaptation remain unknown. To challenge this gap, we performed UV cross-linking, ligation and sequencing of hybrids (CLASH) in S. aureus to unravel sRNA-RNA interactions with the double stranded ribonuclease III (RNase III) as a bait under conditions that mimic the host environment. Here we report a global analysis of RNA-RNA interactions in MRSA in vivo, which uncovered hundreds of novel sRNA-RNA pairs. Strikingly, our results indicate that the production of small membrane-permeabilizing toxins is under extensive sRNA-mediated regulation and that their expression is intimately connected to metabolism. We show that at least two sRNAs, RNAIII and RsaE, enhance the production of five clinically relevant cytolytic toxins that are important for survival within the host. Taken together, our data greatly expands the repertoire of sRNA-target interactions in S. aureus and provide detail on how these contribute to adjusting virulence in response to changes in metabolism.
2022-06-16 | PXD025122 | Pride
Project description:PAZ/PIWI-domain (PPD) proteins carrying small RNAs (sRNAs) function in gene and genome regulation. The ciliate Tetrahymena thermophila encodes numerous PPD proteins exclusively of the Piwi clade. We show that the three Tetrahymena Piwi-family proteins (Twis) preferentially expressed in growing cells differ in their genetic essentiality and subcellular localization. Affinity purification of all eight distinct Twi proteins revealed unique properties of their bound sRNAs. Deep sequencing of Twi-bound and total sRNAs in strains disrupted for various silencing machinery uncovered an unanticipated diversity of 23-24 nt sRNA classes in growing cells, each with distinct genetic requirements for accumulation. Altogether Twis distinguish sRNAs derived from loci of pseudogene families, three types of DNA repeats, structured RNAs, and EST-supported loci with convergent or paralogous transcripts. Most surprisingly, Twi7 binds complementary strands of unequal length while Twi10 binds a specific permutation of the guanosine-rich telomeric repeat. These studies greatly expand the structural and functional repertoire of endogenous sRNAs and RNPs. 11 libraries were analyzed. 5 are total sRNA (from knockout strains or WT background strains), and 6 are Argonaute-bound sRNA
2009-11-23 | E-GEOD-17006 | biostudies-arrayexpress
Project description:We identified twin small non-coding RNAs regulating tricarboxylic acid (TCA) cycle activity in Neisseria meningitidis. Expression of TCA cycle enzymes was elevated in sRNA deletion mutants. Direct interaction between sRNAs and the ribosomal entry sites on target mRNAs was demonstrated. Expression of the sRNAs was down-regulated in cells grown in poor medium with glucose as the sole carbon source but not without lrp, indicating that sRNA expression is controlled by the stringent response. N. meningitidis, over-expressing the sRNAs replicated in blood, but not in human cerebrospinal fluid. In addition, Lrp synthesis was inhibited by direct interaction between the sRNA and the 5’ UTR of lrp. sRNAs control adaptation of N. meningitidis to variation in nutrient supply in different niches of its host.
2017-03-22 | PXD000891 | Pride