Transposon mutagenesis paired with deep sequencing of Caulobacter crescentus under uranium stress reveals genes essential for detoxification and stress tolerance
In: Journal of Bacteriology, Jg. 197 (2015-12-01), Heft 23-24, S. 3160-3172
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Zugriff:
The ubiquitous aquatic bacterium Caulobacter crescentus is highly resistant to uranium (U) and facilitates U biomineralization and thus holds promise as an agent of U bioremediation. To gain an understanding of how C. crescentus tolerates U, we employed transposon (Tn) mutagenesis paired with deep sequencing (Tn-seq) in a global screen for genomic elements required for U resistance. Of the 3,879 annotated genes in the C. crescentus genome, 37 were found to be specifically associated with fitness under U stress, 15 of which were subsequently tested through mutational analysis. Systematic deletion analysis revealed that mutants lacking outer membrane transporters (rsaFa and rsaFb), a stress-responsive transcription factor (cztR), or a ppGpp synthetase/hydrolase (spoT) exhibited a significantly lower survival rate under U stress. RsaFa and RsaFb, which are homologues of TolC in Escherichia coli, have previously been shown to mediate S-layer export. Transcriptional analysis revealed upregulation of rsaFa and rsaFb by 4- and 10-fold, respectively, in the presence of U. We additionally show that rsaFa mutants accumulated higher levels of U than the wild type, with no significant increase in oxidative stress levels. Our results suggest a function for RsaFa and RsaFb in U efflux and/or maintenance of membrane integrity during U stress. In addition, we present data implicating CztR and SpoT in resistance to U stress. Together, our findings reveal novel gene targets that are key to understanding the molecular mechanisms of U resistance in C. crescentus.
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Transposon mutagenesis paired with deep sequencing of Caulobacter crescentus under uranium stress reveals genes essential for detoxification and stress tolerance
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Autor/in / Beteiligte Person: | Yung, Mimi C. ; Park, Dan M. ; Overton, K. Wesley ; Blow, Matthew J. ; Hoover, Cindi A. ; Smit, John ; Murray, Sean R. ; Ricci, Dante P. ; Christen, Beat ; Bowman, Grant R. ; Jiao, Yongqin |
Zeitschrift: | Journal of Bacteriology, Jg. 197 (2015-12-01), Heft 23-24, S. 3160-3172 |
Veröffentlichung: | 2015 |
Medientyp: | academicJournal |
ISSN: | 0021-9193 (print) |
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