Overexpression of a histone-like nucleoid structuring protein in Burkholderia multivorans affects several traits dependent on the cell envelope
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PROVIDER: PRJNA682621 | ENA |
REPOSITORIES: ENA
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Project description:Burkholderia cepacia complex bacteria comprise opportunistic pathogens causing chronic respiratory infections in cystic fibrosis (CF) patients. These microorganisms produce exopolysaccharides which are considered virulence determinants. Here, we report the isolation of an evolved nonmucoid variant (17616nmv) after the ancestor, Burkholderia multivorans ATCC 17616, was subjected to prolonged stationary phase. Lack of exopolysaccharide cepacian biosynthesis in the variant was correlated with downregulation of bce genes expression. Furthermore, genome sequence of the variant identified the transposition of a mobile element of the IS406 family into the promoter region of an hns-like gene (Bmul_0158) encoding a histone-like nucleoid structuring protein, a known global transcriptional repressor. This IS element upregulated the expression of Bmul_0158 gene. Transcriptome analysis identified the global effects of this mutation on gene expression, with major changes in motility, pili synthesis, type VI secretion, and chromosome associated functions. Concomitant with these differences, the nonmucoid variant displays reduced adherence to a CF lung bronchial cell line, reduced surface hydrophobicity, forms smaller cellular aggregates, but has an increase in swimming and swarming motilities. Finally, bioinformatic analysis led to the identification of various genomic regions, possibly acquired by horizontal gene transfer, which were transcriptionally repressed by the increased expression of hns gene in the nonmucoid variant. Taken together, our results revealed a significant role for this H-NS protein in the regulation of B. multivorans persistence- and virulence-associated genes.
2021-04-26 | GSE162693 | GEO
Project description:Burkholderia cepacia complex bacteria comprise opportunistic pathogens causing chronic respiratory infections in cystic fibrosis (CF) patients. These microorganisms produce an exopolysaccharide named cepacian, which is considered a virulence determinant. To find genes implicated in the regulation of cepacian biosynthesis, we characterized an evolved nonmucoid variant (17616nmv) derived from the ancestor, Burkholderia multivorans ATCC 17616, after prolonged stationary phase. Lack of cepacian biosynthesis was correlated with downregulation of the expression of bce genes implicated in its biosynthesis. Furthermore, genome sequencing of the variant identified the transposition of the mobile element IS406 upstream of the coding sequence of an hns-like gene (Bmul_0158) encoding a histone-like nucleoid structuring (H-NS) protein, a known global transcriptional repressor. This insertion sequence (IS) element upregulated the expression of Bmul_0158 by 4-fold. Transcriptome analysis identified the global effects of this mutation on gene expression, with major changes in genes implicated in motility, pilus synthesis, type VI secretion, and chromosome-associated functions. Concomitant with these differences, the nonmucoid variant displays reduced adherence to a CF lung bronchial cell line and reduced surface hydrophobicity and forms smaller cellular aggregates but has an increase in swimming and swarming motilities. Finally, analysis of the GC content of the upstream region of differentially expressed genes led to the identification of various genomic regions, possibly acquired by horizontal gene transfer, which were transcriptionally repressed by the increased expression of the Bmul_0158 gene in the 17616nmv strain. Taken together, the results revealed a significant role for this H-NS protein in the regulation of B. multivorans persistence- and virulence-associated genes. IMPORTANCE Members of the histone-like nucleoid structuring (H-NS) family of proteins, present in many bacteria, are important global regulators of gene expression. Many of the regulated genes were acquired horizontally and include pathogenicity islands and prophages, among others. Additionally, H-NS can play a structural role by bridging and compacting DNA, fulfilling a crucial role in cell physiology. Several virulence phenotypes have been frequently identified in several bacteria as dependent on H-NS activity. Here, we describe an H-NS-like protein of the opportunistic pathogen Burkholderia multivorans, a species commonly infecting the respiratory tract of cystic fibrosis patients. Our results indicate that this protein is involved in regulating virulence traits such as exopolysaccharide biosynthesis, adhesion to biotic surfaces, cellular aggregation, and motility. Furthermore, this H-NS-like protein is one out of eight orthologs present in the B. multivorans ATCC 17616 genome, posing relevant questions to be investigated on how these proteins coordinate the expression of virulence traits.
| S-EPMC8231446 | biostudies-literature
Project description:Multiscale structuring of the E. coli chromosome by nucleoid-associated and condensin proteins
| PRJNA421326 | ENA
Project description:Cholera is a diarrheal disease caused by Vibrio cholerae of serogroups O1 and O139 that affects impoverished populations worldwide. The histone-like nucleoid structuring protein (H-NS) is a global regulator of environmentally-regulated gene expression that plays a fundamental role in V. cholerae adaptation to disparate ecological niches. We used RNA-seq to characterize the hns transcriptome of El Tor biotype V. cholerae. H-NS affected the expression of 18% of all predicted genes in a growth phase-dependent manner. It silenced the transcription of genes encoding virulence regulators and cytotoxic factors such as the VieSAB regulatory system, the repeat in toxin (RTX) and hemolysin. H-NS was 10 times more effective in silencing the vieSAB promoter in El Tor compared to classical biotype V. cholerae. In the El Tor biotype hns mutant, VieSAB significantly enhanced the expression of cholera toxin genes. For the RTX and hemolysin, we found that overexpression of the transcription activator HlyU diminished H-NS occupancy at the hlyA promoter but not at the rtxCA and rtxBDE promoters. H-NS had a significant impact on the cell envelope and the mutant expressed elevated rpoE encoding the extracytoplamic sigma factor E (sE), though this effect was indirect. A remarkable feature of the hns transcriptome was the down-regulation of numerous methyl-accepting chemotaxis proteins in early stationary phase that translated into diminished chemotaxis toward the amino acids glycine and serine. Our study suggests that H-NS transcriptional silencing can contribute to multiple phenotypic differences observed between V. cholerae biotypes, mainly by differentially repressing the VieSAB sensory pathway. Transcriptome profiles of wild type and M-NM-^Thns mutant cells of the V. cholerae strain C7258 grown in LB medium were generated by Next Generation Sequencing using the Illumina HiSeq2000 platform. Samples from mid-exponential phase (OD600 0.5) and early stationary phase (OD600 2.0) were analyzed in duplicate
2015-02-16 | E-GEOD-62785 | biostudies-arrayexpress
Project description:Cholera is a diarrheal disease caused by Vibrio cholerae of serogroups O1 and O139 that affects impoverished populations worldwide. The histone-like nucleoid structuring protein (H-NS) is a global regulator of environmentally-regulated gene expression that plays a fundamental role in V. cholerae adaptation to disparate ecological niches. We used RNA-seq to characterize the hns transcriptome of El Tor biotype V. cholerae. H-NS affected the expression of 18% of all predicted genes in a growth phase-dependent manner. It silenced the transcription of genes encoding virulence regulators and cytotoxic factors such as the VieSAB regulatory system, the repeat in toxin (RTX) and hemolysin. H-NS was 10 times more effective in silencing the vieSAB promoter in El Tor compared to classical biotype V. cholerae. In the El Tor biotype hns mutant, VieSAB significantly enhanced the expression of cholera toxin genes. For the RTX and hemolysin, we found that overexpression of the transcription activator HlyU diminished H-NS occupancy at the hlyA promoter but not at the rtxCA and rtxBDE promoters. H-NS had a significant impact on the cell envelope and the mutant expressed elevated rpoE encoding the extracytoplamic sigma factor E (sE), though this effect was indirect. A remarkable feature of the hns transcriptome was the down-regulation of numerous methyl-accepting chemotaxis proteins in early stationary phase that translated into diminished chemotaxis toward the amino acids glycine and serine. Our study suggests that H-NS transcriptional silencing can contribute to multiple phenotypic differences observed between V. cholerae biotypes, mainly by differentially repressing the VieSAB sensory pathway.
2015-02-16 | GSE62785 | GEO
Project description:As in Eukaryotes, bacterial genomes are not randomly folded. Bacterial genetic information is generally carried on a circular chromosome with a single origin of replication from which two replication forks proceed bidirectionaly towards the opposite terminus region. Here we investigate the higher-order architecture of the Escherichia coli genome, showing its partition into two structuraly distinct entities by a complex and intertwined network of contacts: the replication terminus (ter) region and the rest of the chromosome. Outside ter, the condensin MukBEF and the ubiquitous nucleoid-associated protein (NAP) HU promote DNA contacts in the megabase range. Within ter, the MatP protein prevents MukBEF activity and contacts are restricted to ~280 kb creating a domain with distinct structural properties. We also show how other NAPs contribute to nucleoid organization, such as H-NS that restricts short-range interactions. Combined, these results reveal the contributions of major, evolutionary conserved proteins in a bacterial chromosome organization.
2017-12-07 | GSE107301 | GEO
Project description:The cholera disease bacterium V. cholerae, can adopt planktonic or biofilm lifestyles depending on the intracellular concentration of the second messenger cyclic diguanylic acid (c-di-GMP). Biofilm formation protects Vibrios from stressful conditions and facilitates disease transmission by enhancing infectivity. The histone-like nucleoid structuring protein (H-NS) is a global regulator of genes associated with pathogenicity and responses to environmental stresses. H-NS represses the transcription of genes vpsT, vpsA and vpsL, which are required for the biosynthesis of the biofilm exopolysacchide matrix. Here we demonstrate that the c-di-GMP-binding protein VpsT disrupts H-NS nucleoprotein complexes at the vpsA and vpsL promoters and that this effect is enhanced by c-di-GMP. We used ChIP coupled with Next Generation Sequencing (ChIP-Seq) and transcriptome analysis (RNA-Seq) to identify additional loci repressed by H-NS affecting biofilm formation. This study showed that H-NS directly represses the transcription of genes encoding proteins present in the biofilm matrix such as the rbmA-F cluster, hemolysin and chitinase. Similar to vpsA and vpsL, the promoter region of vpsU, rbmA and rbmF exhibited overlapping H-NS and VpsT binding motifs. Deletion of vpsT increased H-NS occupancy at the vpsU, vpsA, vpsL, rbmA and rbmF promoters. Conversely, artificially increasing the c-di-GMP pool diminished H-NS occupancy at the above promoters. Deletion of vpsT did not affect H-NS occupancy at its own promoter. However, deletion of genes encoding the regulators AphA and VpsR significantly increased H-NS occupancy at the vpsT promoter. In sum, our study shows that c-di-GMP enhances biofilm formation by acting through VpsT to activate an H-NS anti-repression cascade. The Binding profile of V. cholerae H-NS to the genome was determined by ChIP followed by Next Generation Sequencing (ChIP-Seq) using the Illumina HiSeq2000 platform. V. cholerae C7258 cells expressing H-NS-FLAG fusion protein from the hns transcription and translation signals were collected from LB cultures grown to mid-exponential phase (OD600 0.5). An anti-FLAG Immunoprecipitation (IP) and an Input samples were used for the analysis.
2015-05-13 | E-GEOD-64249 | biostudies-arrayexpress
Project description:Nucleoid-associated proteins (NAPs) are small, highly abundant regulators with low sequence specificity and pleiotropic mutant phenotypes. They are involved in transcriptional and post-transcriptional control of gene expression, DNA protection/repair and nucleoid structuring. Discovery of the major NAPs has been largely haphazard and based with the Enterobacteriaceae, although some Actinomycete-specific NAPs (Mdp1, Lsr2, sIHF) are known. Here, we use LC-MS/MS to systematically search for novel NAPs in isolated nucleoids of the model actinomycete Streptomyces coelicolor. Based on the criteria of high abundance (emPAI) and predicted DNA-binding ability (DNAbinder) we identified a set of around twenty proteins with a good probability of being NAPs. The approach was apparently successful as the set included known major NAPs HupA, sIHF and Lsr2 as well as the global regulators BldD and CRP. It also included a number of proteins whose functions are not yet known (SCO0204, SCO3013, SCO4232, SCO4199 and SCO1839) which provide a useful set of candidates for further study.
2013-04-24 | PRD000736 | Pride
Project description:The cholera disease bacterium V. cholerae, can adopt planktonic or biofilm lifestyles depending on the intracellular concentration of the second messenger cyclic diguanylic acid (c-di-GMP). Biofilm formation protects Vibrios from stressful conditions and facilitates disease transmission by enhancing infectivity. The histone-like nucleoid structuring protein (H-NS) is a global regulator of genes associated with pathogenicity and responses to environmental stresses. H-NS represses the transcription of genes vpsT, vpsA and vpsL, which are required for the biosynthesis of the biofilm exopolysacchide matrix. Here we demonstrate that the c-di-GMP-binding protein VpsT disrupts H-NS nucleoprotein complexes at the vpsA and vpsL promoters and that this effect is enhanced by c-di-GMP. We used ChIP coupled with Next Generation Sequencing (ChIP-Seq) and transcriptome analysis (RNA-Seq) to identify additional loci repressed by H-NS affecting biofilm formation. This study showed that H-NS directly represses the transcription of genes encoding proteins present in the biofilm matrix such as the rbmA-F cluster, hemolysin and chitinase. Similar to vpsA and vpsL, the promoter region of vpsU, rbmA and rbmF exhibited overlapping H-NS and VpsT binding motifs. Deletion of vpsT increased H-NS occupancy at the vpsU, vpsA, vpsL, rbmA and rbmF promoters. Conversely, artificially increasing the c-di-GMP pool diminished H-NS occupancy at the above promoters. Deletion of vpsT did not affect H-NS occupancy at its own promoter. However, deletion of genes encoding the regulators AphA and VpsR significantly increased H-NS occupancy at the vpsT promoter. In sum, our study shows that c-di-GMP enhances biofilm formation by acting through VpsT to activate an H-NS anti-repression cascade.
2015-05-13 | GSE64249 | GEO
Project description:Burkholderia multivorans comprises opportunistic bacteria infecting hosts such as cystic fibrosis (CF) patients. Bcc long-term infection of CF patient airways has been associated with emergence of phenotypic variation including the mucoid-to-nonmucoid colony morphotype. Here we studied three Burkholderia multivorans clonal isolates (mucoid D2095 (BM11L), and nonmucoid D2214G and D2214P) and a laboratory nonmucoid variant (BM11L-nmv1) obtained under prolonged stationary phase. The aim is to identify possible traits associated to the different morphotypes and find possible mechanisms for this morphotypic variation.
2018-06-22 | GSE111467 | GEO