Redefining the sRNA transcriptome of Streptococcus pneumoniae serotype 2 strain D39
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ABSTRACT:
ORGANISM(S): Streptococcus pneumoniae D39
PROVIDER: GSE123437 | GEO | 2019/03/11
REPOSITORIES: GEO
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Project description:Streptococcus pneumoniae (pneumococcus) is a major human respiratory pathogen and a leading cause of bacterial pneumonia worldwide. Small regulatory RNAs (sRNAs), which often act by post-transcriptionally regulating gene expression, have been shown to be crucial for the virulence of S. pneumoniae and other bacterial pathogens. Over 170 putative sRNAs have been identified in S. pneumoniae TIGR4 strain (serotype 4) through transcriptomic studies, and a subset of these sRNAs have been further implicated in regulating pneumococcal pathogenesis. However, there is little overlap in the sRNAs identified among these studies, which indicates that the approaches used for sRNA identification were not sufficiently sensitive and robust and that there are likely many more undiscovered sRNAs encoded in the S. pneumoniae genome. Here, we sought to comprehensively identify sRNAs in Avery's virulent S. pneumoniae strain D39 using two independent RNA-seq based approaches. We developed an unbiased method for identifying novel sRNAs from bacterial RNA-seq data and have further tested the specificity of our analysis program towards identifying sRNAs encoded by both strains D39 and TIGR4. Interestingly, the genes for 15% of the putative sRNAs identified in strain TIGR4 including ones previously implicated in virulence are not present in strain D39 genome suggesting that the differences in sRNA repertoires between these two serotypes may contribute to their strain-specific virulence properties. Finally, this study has identified 67 new sRNA candidates in strain D39, 28 out of which have been further validated, raising the total number of sRNAs that have been identified in strain D39 to 112.
2019-05-13 | GSE124170 | GEO
Project description:RNases perform indispensable functions in regulating gene expression in many bacterial pathogens by processing and/or degrading RNAs. Despite the pivotal role of RNases in regulating bacterial virulence factors, the functions of RNases have not yet been studied in the major human respiratory pathogen Streptococcus pneumoniae (pneumococcus). Here, we sought to determine the impact of two conserved RNases, the endoribonuclease RNase Y and exoribonuclease polynucleotide phosphorylase (PNPase), on the physiology and virulence of S. pneumoniae serotype 2 strain D39. We report that RNase Y and PNPase are essential for pneumococcal pathogenesis as both deletion mutants showed strong attenuation of virulence in murine models of invasive pneumonia. Genome-wide transcriptomic analysis revealed that nearly 200 mRNA transcripts were significantly up-regulated, whereas the abundance of several pneumococcal sRNAs, including the Ccn (CiaR Controlled Noncoding RNA) sRNAs, were altered in the ∆rny mutant relative to the wild-type strain. Additionally, lack of RNase Y resulted in pleiotropic phenotypes that included defects in pneumococcal cell morphology and growth in vitro. In contrast, Dpnp mutants showed no growth defect in vitro, but differentially expressed a total of 40 transcripts including the tryptophan biosynthesis operon genes and numerous 5’-cis-acting regulatory RNAs, a majority of which were previously shown to impact pneumococcal disease progression in mice using the serotype 4 strain TIGR4. Altogether our data suggest that RNase Y exerts a global impact on pneumococcal physiology, while PNPase-mediates virulence phenotypes, likely through sRNA regulation.
2021-09-02 | GSE173392 | GEO
Project description:Previous studies have indicated that PsaR of Streptococcus pneumoniae is a manganese-dependent regulator, negatively affecting the expression of at least seven genes. Here, we extended these observations by transcriptome and proteome analysis of psaR mutants in strains D39 and TIGR4. The microarray analysis identified three shared PsaR targets: the psa-operon, pcpA, and prtA. Additionally, we found 31 genes to be regulated by PsaR in D39 only, most strikingly a cellobiose-specific PTS and a putative bacteriocin operon (sp0141-sp0146). In TIGR4, 14 PsaR gene targets were detected, with the rlrA pathogenicity islet being the most pronounced. Proteomics confirmed most of the shared gene targets. To examine the contribution of PsaR to pneumococcal virulence, we compared D39 and TIGR4 wild-type (wt) and psaR-mutants in three murine infection models. During colonization, no clear effect was observed of the psaR mutation in either D39 or TIGR4. In the pneumonia model, small but significant differences were observed in the lungs of mice infected with either D39wt or ∆psaR: D39∆psaR had an initial advantage in survival in the lungs. Conversely, TIGR4∆psaR-infected mice had significantly lower bacterial loads at 24h only. Finally, during experimental bacteremia, D39∆psaR-infected mice had significantly lower bacterial loads in the blood stream than wt-infected mice for the first 24h of infection. TIGR4∆psaR showed attenuation at 36h only. In conclusion, our results show that PsaR of D39 and TIGR4 has a strain-specific role in global gene expression and in the development of bacteremia in mice.
2008-11-19 | GSE13505 | GEO
Project description:Recent murine studies have demonstrated that the role of response regulator 09 (RR09) of S. pneumoniae in virulence varies between strains. In the present study, we used a murine pneumonia model of infection to assess the virulence of a TIGR4 rr09-mutant, and found that TIGR4Δrr09 was attenuated after intranasal infection. Further, we investigated the in vitro transcriptional changes in pneumococcal rr09 mutants of two strains, D39 and TIGR4, by microarray analysis. The transcriptional profiles of the rr09 mutants in both strains displayed clear differences compared to their parental wild-type. In D39Δrr09 but not TIGR4Δrr09, genes involved in competence (e.g. comAB) were upregulated. In TIGR4, genes located on the rlrA pathogenicity islet, absent in the D39 genome, appeared to be regulated by RR09. Furthermore, several phosphotransferase systems (PTSs), believed to be involved in sugar uptake (e.g., sp0060-sp0066), were strongly downregulated in D39Δrr09, while not regulated by RR09 in TIGR4. To address the role of one of these PTS in virulence, D39Δsp0063 was constructed and tested in a murine infection model. No difference in virulence compared to the wild-type was found, indicating that downregulation of this gene alone is not the cause of the avirulent phenotype of D39Δrr09. Finally, expression of rr09 and three of our identified RR09 targets were assessed during infection in mice. This in vivo experiment confirmed differences in expression between TIGR4 wild-type and rr09-mutant, as well as between wild-type D39 and TIGR4. In conclusion, our results indicate strain specific regulation of pneumococcal gene expression by RR09. Keywords: Genetic modification
2006-10-28 | GSE6139 | GEO
Project description:Recent murine studies have demonstrated that the role of response regulator 09 (RR09) of S. pneumoniae in virulence varies between strains. In the present study, we used a murine pneumonia model of infection to assess the virulence of a TIGR4 rr09-mutant, and found that TIGR4Δrr09 was attenuated after intranasal infection. Further, we investigated the in vitro transcriptional changes in pneumococcal rr09 mutants of two strains, D39 and TIGR4, by microarray analysis. The transcriptional profiles of the rr09 mutants in both strains displayed clear differences compared to their parental wild-type. In D39Δrr09 but not TIGR4Δrr09, genes involved in competence (e.g. comAB) were upregulated. In TIGR4, genes located on the rlrA pathogenicity islet, absent in the D39 genome, appeared to be regulated by RR09. Furthermore, several phosphotransferase systems (PTSs), believed to be involved in sugar uptake (e.g., sp0060-sp0066), were strongly downregulated in D39Δrr09, while not regulated by RR09 in TIGR4. To address the role of one of these PTS in virulence, D39Δsp0063 was constructed and tested in a murine infection model. No difference in virulence compared to the wild-type was found, indicating that downregulation of this gene alone is not the cause of the avirulent phenotype of D39Δrr09. Finally, expression of rr09 and three of our identified RR09 targets were assessed during infection in mice. This in vivo experiment confirmed differences in expression between TIGR4 wild-type and rr09-mutant, as well as between wild-type D39 and TIGR4. In conclusion, our results indicate strain-specific regulation of pneumococcal gene expression by RR09. Keywords: genetic modification
2006-12-24 | GSE6137 | GEO
Project description:Streptococcus pneumoniae (pneumococcus) is a leading human respiratory pathogen that causes a variety of serious mucosal and invasive diseases. D39 is an historically important serotype 2 strain that was used in experiments by Avery and coworkers to demonstrate that DNA is the genetic material. Although isolated nearly a century ago, D39 remains extremely virulent in murine infection models and is perhaps the strain used most frequently in current studies of pneumococcal pathogenicity. To date, the complete genome sequences have been reported for only two S. pneumoniae strains; TIGR4, a recent serotype 4 clinical isolate, and laboratory strain R6, an avirulent, unencapsulated derivative of strain D39. We report herein the genome sequences of two different isolates of strain D39 and the corrected sequence and updated annotation of strain R6. Comparisons of these three related sequences allowed deduction of the likely sequence of the D39 progenitor and mutations that arose in each isolate. Despite its numerous repeated sequences and IS elements, the serotype 2 genome has remained remarkably stable during cultivation, and one of the D39 isolates contains only 5 relatively minor mutations compared to the deduced D39 progenitor. In contrast, laboratory strain R6 contains 71 single base pair changes, 6 deletions, 4 insertions, and has lost the cryptic pDP1 plasmid compared to the D39 progenitor strain. Many of these mutations are in or affect the expression of genes that play important roles in regulation, metabolism, and virulence. The nature of the mutations that arose spontaneously in these three strains, relative global transcription patterns determined by microarray analyses, and the implications of the D39 genome sequences to studies of pneumococcal physiology and pathogenesis are presented and discussed. Keywords: bacterial strain comparison, bacterial isolate comparison
2006-10-09 | GSE5375 | GEO
Project description:Previous studies have indicated that PsaR of Streptococcus pneumoniae is a manganese-dependent regulator, negatively affecting the expression of at least seven genes. Here, we extended these observations by transcriptome and proteome analysis of psaR mutants in strains D39 and TIGR4. The microarray analysis identified three shared PsaR targets: the psa-operon, pcpA, and prtA. Additionally, we found 31 genes to be regulated by PsaR in D39 only, most strikingly a cellobiose-specific PTS and a putative bacteriocin operon (sp0141-sp0146). In TIGR4, 14 PsaR gene targets were detected, with the rlrA pathogenicity islet being the most pronounced. Proteomics confirmed most of the shared gene targets. To examine the contribution of PsaR to pneumococcal virulence, we compared D39 and TIGR4 wild-type (wt) and psaR-mutants in three murine infection models. During colonization, no clear effect was observed of the psaR mutation in either D39 or TIGR4. In the pneumonia model, small but significant differences were observed in the lungs of mice infected with either D39wt or âpsaR: D39âpsaR had an initial advantage in survival in the lungs. Conversely, TIGR4âpsaR-infected mice had significantly lower bacterial loads at 24h only. Finally, during experimental bacteremia, D39âpsaR-infected mice had significantly lower bacterial loads in the blood stream than wt-infected mice for the first 24h of infection. TIGR4âpsaR showed attenuation at 36h only. In conclusion, our results show that PsaR of D39 and TIGR4 has a strain-specific role in global gene expression and in the development of bacteremia in mice. Microarray analysis was performed essentially as described (Hendriksen et al., 2007; Hendriksen et al., 2008a). In short, 500 ml of CDM was inoculated with 10-20 colonies from agar plates, and these cultures were statically grown at 37°C. Samples for RNA isolation were taken when the cultures reached an optical density (OD600) of 0.2 (mid-log growth). RNA was isolated and purified using the High Pure RNA isolation kit (Roche diagnostics) as described (Hendriksen et al., 2007; Hendriksen et al., 2008a). Contaminating genomic DNA was removed by treatment with RNase-free DNase I (Roche diagnostics). RNA was isolated from three replicate cultures. Synthesis, subsequent labeling of cDNA, and microarray hybridization was performed as described (Hendriksen et al., 2007; Kloosterman et al., 2006). In all cases, dye-swapping was performed with one of the three biological replicates. Microarrays used in this study were constructed as described (Hendriksen et al., 2007; Kloosterman et al., 2006) and contain amplicons representing 2,087 ORFs of S. pneumoniae TIGR4 and 184 ORFs unique for S. pneumoniae R6, all spotted in duplicate.
2010-05-15 | E-GEOD-13505 | biostudies-arrayexpress
Project description:We report here an experimental search for small non-coding RNAs in a low GC, gram-positive, human pathogenic bacteria Streptococcus pneumoniae. Based on the bioinformatic analyses by Livny et al. (2006, Nucleic Acids Res. 34:3484-93), we tested 36 candidates by Northern analyses and confirmed the expression of 8 novel and one previously-reported sRNAs (CcnA) in the genome of D39 serotype 2 strain. Some of the sRNAs showed differential expression in stationary phase or after treatment with competence stimulatory peptide compared to untreated exponential cells. One sRNA we detected is CcnA, one of five CiaR-controlled non-coding RNA (CcnA to E) reported previously. By ectopically expressing this sRNA in a ΔciaR strain, we provide evidence that CcnA plays important roles in the regulation of growth and chain length of S. pneumoniae. Microarray analysis comparing global gene expression of CcnA-expressing and CcnA-nonexpressing ΔciaR strains showed significant differences in expression of competence related genes and five putative transcriptional regulators. QPCR and transformation assays further confirmed that CcnA sRNA mediates a strong negative effect on competence development. Our findings suggested many of the CiaRH function may be mediated via Ccn sRNAs and that sRNAs play regulatory roles in S. pneumoniae, an organism that lacks Hfq RNA chaperone.
2010-02-03 | GSE14688 | GEO
Project description:We report here an experimental search for small non-coding RNAs in a low GC, gram-positive, human pathogenic bacteria Streptococcus pneumoniae. Based on the bioinformatic analyses by Livny et al. (2006, Nucleic Acids Res. 34:3484-93), we tested 36 candidates by Northern analyses and confirmed the expression of 8 novel and one previously-reported sRNAs (CcnA) in the genome of D39 serotype 2 strain. Some of the sRNAs showed differential expression in stationary phase or after treatment with competence stimulatory peptide compared to untreated exponential cells. One sRNA we detected is CcnA, one of five CiaR-controlled non-coding RNA (CcnA to E) reported previously. By ectopically expressing this sRNA in a ÎciaR strain, we provide evidence that CcnA plays important roles in the regulation of growth and chain length of S. pneumoniae. Microarray analysis comparing global gene expression of CcnA-expressing and CcnA-nonexpressing ÎciaR strains showed significant differences in expression of competence related genes and five putative transcriptional regulators. QPCR and transformation assays further confirmed that CcnA sRNA mediates a strong negative effect on competence development. Our findings suggested many of the CiaRH function may be mediated via Ccn sRNAs and that sRNAs play regulatory roles in S. pneumoniae, an organism that lacks Hfq RNA chaperone. Three independent hybridizations using independent RNA preparations from the strain IU2678 (a ciaR knockout strain with no ccnA expression, reference strain) and strain IU2841 (a ciaR knowckout strain with ccnA expression at an ectopic site) were performed. Dye swap was performed with the reference strain labeled with Cy3 in two hybridizations and Cy5 in the one hybridizations.
2010-05-14 | E-GEOD-14688 | biostudies-arrayexpress
Project description:Phage-like elements are found in a multitude of streptococcal species, including pneumococcal strain Hungary19A-6 (SpnCI). The aim of our research was to investigate the role of phage-like element SpnCI in enhanced virulence and phenotypic modulation within Streptococcus pneumoniae. SpnCI was found to significantly enhance virulence within the invertebrate infection model Galleria mellonella. Infections with SpnCI led to a lower mean health score (1.6) and survival percentage (20%) compared to SpnCI null TIGR4 infections (3.85 mean health score and 50% survival). SpnCI remained integrated throughout growth, conferring greater sensitivity to UV irradiation. Change in transcriptional patterns occurred, including downregulation of operons involved with cell surface modelling in the SpnCI containing strain of TIGR4. Kanamycin-tagged SpnCI strain in Hungary19A-6 was inducible and isolated from lysate along with both annotated prophages. No phages were identified by PCR nor electron microscopy (EM) following induction of TIGR4 SpnCI∆strA suggesting helper-phage dependence for dissemination. EM of lysate showed typical siphoviridae morphology with an average capsid size of 60 nm. Two of sixty capsids were found to be smaller, suggesting SpnCI disseminates using a similar mechanism described for Staphylococcus aureus phage-like element SaPI. SpnCI from lysate infected capsule null strain T4R but was incapable of infecting the encapsulated TIGR4 strain suggesting that capsule impedes phage infection. Our work demonstrates that SpnCI can modulate virulence, UV susceptibility, alter transcriptional patterns, and furthermore, can disseminate via infection within pneumococcus. Further research is necessary to elucidate how SpnCI modulates virulence and what genes are responsible for the enhanced virulence phenotype.
2019-06-12 | GSE132556 | GEO