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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Iron Deficiency Generates Oxidative Stress and Activation of the SOS Response in Caulobacter crescentus

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Leaden, Laura [1] ; Silva, Larissa G. [1] ; Ribeiro, Rodolfo A. [1] ; dos Santos, Naara M. [1] ; Lorenzetti, Alan P. R. [2] ; Alegria, Thiago G. P. [3] ; Schulz, Mariane L. [4] ; Medeiros, Marisa H. G. [4] ; Koide, Tie [2] ; Marques, V, Marilis
Total Authors: 10
[1] V, Univ Sao Paulo, Inst Ciencias Biomed, Dept Microbiol, Sao Paulo - Brazil
[2] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Bioquim & Imunol, Ribeirao Preto - Brazil
[3] Univ Sao Paulo, Inst Biociencias, Dept Genet & Biol Evolut, Sao Paulo - Brazil
[4] Univ Sao Paulo, Inst Quim, Dept Bioquim, Sao Paulo - Brazil
Total Affiliations: 4
Document type: Journal article
Web of Science Citations: 5

In C. crescentus, iron metabolism is mainly controlled by the transcription factor Fur (ferric uptake regulator). Iron-bound Fur represses genes related to iron uptake and can directly activate the expression of genes for iron-containing proteins. In this work, we used total RNA sequencing (RNA-seq) of wild type C. crescentus growing in minimal medium under iron limitation and a fur mutant strain to expand the known Fur regulon, and to identify novel iron-regulated genes. The RNA-seq of cultures treated with the iron chelator 2-2-dypiridyl (DP) allowed identifying 256 upregulated genes and 236 downregulated genes, being 176 and 204 newly identified, respectively. Sixteen transcription factors and seven sRNAs were upregulated in iron limitation, suggesting that the response to low iron triggers a complex regulatory network. Notably, lexA along with most of its target genes were upregulated, suggesting that DP treatment caused DNA damage, and the SOS DNA repair response was activated in a RecA-dependent manner, as confirmed by RT-qPCR. Fluorescence microscopy assays using an oxidation-sensitive dye showed that wild type cells in iron limitation and the fur mutant were under endogenous oxidative stress, and a direct measurement of cellular H2O2 showed that cells in iron-limited media present a higher amount of endogenous H2O2. A mutagenesis assay using the rpoB gene as a reporter showed that iron limitation led to an increase in the mutagenesis rate. These results showed that iron deficiency causes C. crescentus cells to suffer oxidative stress and to activate the SOS response, indicating an increase in DNA damage. (AU)

FAPESP's process: 14/04046-8 - Regulatory networks of bacterial stress response
Grantee:Marilis Do Valle Marques
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 16/06378-3 - Characterization of the DEAD-box RNA helicase CC1478 in Caulobacter crescentus and its regulation
Grantee:Rodolfo Alvarenga Ribeiro
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 15/07386-7 - Regulatory RNAs identification in response to iron availability and their mechanisms of action in Caulobacter crescentus
Grantee:Laura Leaden
Support Opportunities: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 17/02127-9 - Characterization of iron transport systems in Caulobacter crescentus
Grantee:Naara Marcondes dos Santos
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 15/21038-1 - The antisense transcriptome of the halophilic archaeon Halobacterium salinarum
Grantee:Tie Koide
Support Opportunities: Regular Research Grants
FAPESP's process: 17/03052-2 - Non-coding RNAs derived from insertion sequences in the halophilic archaeon Halobacterium salinarum NRC-1
Grantee:Alan Péricles Rodrigues Lorenzetti
Support Opportunities: Scholarships in Brazil - Doctorate