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dc.contributor.authorWallenstein, Alexander
dc.contributor.authorRehm, Nadine
dc.contributor.authorBrinkmann, Marina
dc.contributor.authorSelle, Martina
dc.contributor.authorBossuet-Greif, Nadège
dc.contributor.authorSauer, Daniel
dc.contributor.authorBunk, Boyke
dc.contributor.authorSpröer, Cathrin
dc.contributor.authorWami, Haleluya Tesfaye
dc.contributor.authorHomburg, Stefan
dc.contributor.authorvon Bünau, Rudolf
dc.contributor.authorKönig, Simone
dc.contributor.authorNougayrède, Jean-Philippe
dc.contributor.authorOvermann, Jörg
dc.contributor.authorOswald, Eric
dc.contributor.authorMüller, Rolf
dc.contributor.authorDobrindt, Ulrich
dc.date.accessioned2020-09-11T12:47:29Z
dc.date.available2020-09-11T12:47:29Z
dc.date.issued2020-07-15
dc.identifier.citationmSphere. 2020 Jul 29;5(4):]. mSphere. 2020;5(4):e00591-20. Published 2020 Jul 15. doi:10.1128/mSphere.00591-20.en_US
dc.identifier.pmid32669458
dc.identifier.doi10.1128/mSphere.00591-20
dc.identifier.urihttp://hdl.handle.net/10033/622442
dc.description.abstractColibactin is a nonribosomal peptide/polyketide hybrid natural product expressed by different members of the Enterobacteriaceae which can be correlated with induction of DNA double-strand breaks and interference with cell cycle progression in eukaryotes. Regulatory features of colibactin expression are only incompletely understood. We used Escherichia coli strain M1/5 as a model to investigate regulation of expression of the colibactin determinant at the transcriptional level and to characterize regulatory elements located within the colibactin pathogenicity island itself. We measured clbR transcription in vitro and observed that cultivation in defined minimal media led to increased colibactin expression relative to rich media. Transcription of clbR directly responds to iron availability. We also characterized structural DNA elements inside the colibactin determinant involved in ClbR-dependent regulation, i.e., ClbR binding sites and a variable number of tandem repeats located upstream of clbR We investigated the impact of clbR overexpression or deletion at the transcriptome and proteome levels. Moreover, we compared global gene regulation under these conditions with that occurring upon overexpression or deletion of clbQ, which affects the flux of colibactin production. Combining the results of the transcriptome and proteome analyses with indirect measurements of colibactin levels by cell culture assays and an approximate quantification of colibactin via the second product of colibactin cleavage from precolibactin, N-myristoyl-d-asparagine, we demonstrate that the variable number of tandem repeats plays a significant regulatory role in colibactin expression. We identify ClbR as the only transcriptional activator known so far that is specific and essential for efficient regulation of colibactin production.IMPORTANCE The nonribosomal peptide/polyketide hybrid colibactin can be considered a bacterial virulence factor involved in extraintestinal infection and also a procarcinogen. Nevertheless, and despite its genotoxic effect, colibactin expression can also inhibit bacterial or tumor growth and correlates with probiotic anti-inflammatory and analgesic properties. Although the biological function of this natural compound has been studied extensively, our understanding of the regulation of colibactin expression is still far from complete. We investigated in detail the role of regulatory elements involved in colibactin expression and in the growth conditions that promote colibactin expression. In this way, our data shed light on the regulatory mechanisms involved in colibactin expression and may support the expression and purification of this interesting nonribosomal peptide/polyketide hybrid for further molecular characterization.en_US
dc.language.isoenen_US
dc.publisherASMen_US
dc.rightsAttribution-NonCommercial-ShareAlike 4.0 International*
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/4.0/*
dc.subjectRNA-seqen_US
dc.subjectVNTRen_US
dc.subjectcytopathic effecten_US
dc.subjectpolyketideen_US
dc.subjectsecondary metaboliteen_US
dc.titleClbR Is the Key Transcriptional Activator of Colibactin Gene Expression in Escherichia coli.en_US
dc.typeArticleen_US
dc.identifier.eissn2379-5042
dc.contributor.departmentHIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany.en_US
dc.identifier.journalmSphereen_US
dc.source.volume5
dc.source.issue4
refterms.dateFOA2020-09-11T12:47:30Z
dc.source.journaltitlemSphere
dc.source.countryUnited States


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