Bacterial Suppression of RNA Polymerase II-Dependent Host Gene Expression
Asymptomatic bacteriuria (ABU) is a bacterial carrier state in the urinary tract that resembles commensalism at other mucosal sites. ABU strains often lack the virulence factors that characterize uropathogenic Escherichia coli (E. coli) strains and therefore elicit weak innate immune responses in th...
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| Format: | Article |
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MDPI AG
2016-07-01
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| Series: | Pathogens |
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| Online Access: | http://www.mdpi.com/2076-0817/5/3/49 |
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| author | Ines Ambite Nataliya Lutay Christoph Stork Ulrich Dobrindt Björn Wullt Catharina Svanborg |
| author_facet | Ines Ambite Nataliya Lutay Christoph Stork Ulrich Dobrindt Björn Wullt Catharina Svanborg |
| author_sort | Ines Ambite |
| collection | DOAJ |
| description | Asymptomatic bacteriuria (ABU) is a bacterial carrier state in the urinary tract that resembles commensalism at other mucosal sites. ABU strains often lack the virulence factors that characterize uropathogenic Escherichia coli (E. coli) strains and therefore elicit weak innate immune responses in the urinary tract. In addition, ABU strains are active modifiers of the host environment, which they influence by suppressing RNA polymerase II (Pol II)-dependent host gene expression. In patients inoculated with the ABU strain E. coli 83972, gene expression was markedly reduced after 24 h (>60% of all regulated genes). Specific repressors and activators of Pol II-dependent transcription were modified, and Pol II Serine 2 phosphorylation was significantly inhibited, indicating reduced activity of the polymerase. This active inhibition included disease–associated innate immune response pathways, defined by TLR4, IRF-3 and IRF-7, suggesting that ABU strains persist in human hosts by active suppression of the antibacterial defense. In a search for the mechanism of inhibition, we compared the whole genome sequences of E. coli 83972 and the uropathogenic strain E. coli CFT073. In addition to the known loss of virulence genes, we observed that the ABU strain has acquired several phages and identified the lytic Prophage 3 as a candidate Pol II inhibitor. Intact phage particles were released by ABU during in vitro growth in human urine. To address if Prophage 3 affects Pol II activity, we constructed a Prophage 3 negative deletion mutant in E. coli 83972 and compared the effect on Pol II phosphorylation between the mutant and the E. coli 83972 wild type (WT) strains. No difference was detected, suggesting that the Pol II inhibitor is not encoded by the phage. The review summarizes the evidence that the ABU strain E. coli 83972 modifies host gene expression by inhibition of Pol II phosphorylation, and discusses the ability of ABU strains to actively create an environment that enhances their persistence. |
| first_indexed | 2024-04-12T19:36:39Z |
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| language | English |
| last_indexed | 2024-04-12T19:36:39Z |
| publishDate | 2016-07-01 |
| publisher | MDPI AG |
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| series | Pathogens |
| spelling | doaj.art-ae31fe43550a4a79b21d81f9afc3436c2022-12-22T03:19:12ZengMDPI AGPathogens2076-08172016-07-01534910.3390/pathogens5030049pathogens5030049Bacterial Suppression of RNA Polymerase II-Dependent Host Gene ExpressionInes Ambite0Nataliya Lutay1Christoph Stork2Ulrich Dobrindt3Björn Wullt4Catharina Svanborg5Department of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, 22184 Lund, SwedenDepartment of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, 22184 Lund, SwedenInstitute of Hygiene, University Hospital Münster, Westfälische Wilhelms-Universität, 48149 Münster, GermanyInstitute of Hygiene, University Hospital Münster, Westfälische Wilhelms-Universität, 48149 Münster, GermanyDepartment of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, 22184 Lund, SwedenDepartment of Microbiology, Immunology and Glycobiology, Institute of Laboratory Medicine, Lund University, 22184 Lund, SwedenAsymptomatic bacteriuria (ABU) is a bacterial carrier state in the urinary tract that resembles commensalism at other mucosal sites. ABU strains often lack the virulence factors that characterize uropathogenic Escherichia coli (E. coli) strains and therefore elicit weak innate immune responses in the urinary tract. In addition, ABU strains are active modifiers of the host environment, which they influence by suppressing RNA polymerase II (Pol II)-dependent host gene expression. In patients inoculated with the ABU strain E. coli 83972, gene expression was markedly reduced after 24 h (>60% of all regulated genes). Specific repressors and activators of Pol II-dependent transcription were modified, and Pol II Serine 2 phosphorylation was significantly inhibited, indicating reduced activity of the polymerase. This active inhibition included disease–associated innate immune response pathways, defined by TLR4, IRF-3 and IRF-7, suggesting that ABU strains persist in human hosts by active suppression of the antibacterial defense. In a search for the mechanism of inhibition, we compared the whole genome sequences of E. coli 83972 and the uropathogenic strain E. coli CFT073. In addition to the known loss of virulence genes, we observed that the ABU strain has acquired several phages and identified the lytic Prophage 3 as a candidate Pol II inhibitor. Intact phage particles were released by ABU during in vitro growth in human urine. To address if Prophage 3 affects Pol II activity, we constructed a Prophage 3 negative deletion mutant in E. coli 83972 and compared the effect on Pol II phosphorylation between the mutant and the E. coli 83972 wild type (WT) strains. No difference was detected, suggesting that the Pol II inhibitor is not encoded by the phage. The review summarizes the evidence that the ABU strain E. coli 83972 modifies host gene expression by inhibition of Pol II phosphorylation, and discusses the ability of ABU strains to actively create an environment that enhances their persistence.http://www.mdpi.com/2076-0817/5/3/49asymptomatic bacteriuriaRNA polymerase IIgene expressiontranscriptional modulationphages |
| spellingShingle | Ines Ambite Nataliya Lutay Christoph Stork Ulrich Dobrindt Björn Wullt Catharina Svanborg Bacterial Suppression of RNA Polymerase II-Dependent Host Gene Expression Pathogens asymptomatic bacteriuria RNA polymerase II gene expression transcriptional modulation phages |
| title | Bacterial Suppression of RNA Polymerase II-Dependent Host Gene Expression |
| title_full | Bacterial Suppression of RNA Polymerase II-Dependent Host Gene Expression |
| title_fullStr | Bacterial Suppression of RNA Polymerase II-Dependent Host Gene Expression |
| title_full_unstemmed | Bacterial Suppression of RNA Polymerase II-Dependent Host Gene Expression |
| title_short | Bacterial Suppression of RNA Polymerase II-Dependent Host Gene Expression |
| title_sort | bacterial suppression of rna polymerase ii dependent host gene expression |
| topic | asymptomatic bacteriuria RNA polymerase II gene expression transcriptional modulation phages |
| url | http://www.mdpi.com/2076-0817/5/3/49 |
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