Iron Deficiency Generates Oxidative Stress and Activation of the SOS Response in Caulobacter crescentus.
Iron Deficiency Generates Oxidative Stress and Activation of the SOS Response in Caulobacter crescentus.
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DOI：
10.3389/fmicb.2018.02014
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发表时间：
2018
影响因子：
5.2
通讯作者：
Marques MV
中科院分区：
文献类型：
--
作者：
Leaden L;Silva LG;Ribeiro RA;Dos Santos NM;Lorenzetti APR;Alegria TGP;Schulz ML;Medeiros MHG;Koide T;Marques MV
月牙草铁代谢主要受转录因子Fur（铁摄取调节因子）控制。铁结合毛皮抑制与铁摄取相关的基因，可以直接激活含铁蛋白基因的表达。在这项工作中，我们使用总RNA测序（RNA-seq）在最小培养基中生长的野生型新月形C.在铁限制和毛皮突变株中扩增已知的毛皮调控基因，并鉴定新的铁调控基因。用铁螯合剂2-2-二吡啶基（DP）处理培养物的RNA-seq鉴定出256个上调基因和236个下调基因，分别为新鉴定的176个和204个。16个转录因子和7个sRNAs在铁限制中上调，表明对低铁的反应触发了一个复杂的调控网络。值得注意的是，lexA及其大部分靶基因上调，表明DP治疗导致DNA损伤，SOS DNA修复反应以reca依赖的方式激活，RT-qPCR证实了这一点。使用氧化敏感染料的荧光显微镜分析显示，铁限制下的野生型细胞和皮毛突变体处于内源性氧化应激状态，细胞H2O2的直接测量表明，铁限制培养基中的细胞存在更高的内源性H2O2。一项以rpoB基因为报告基因的诱变实验表明，铁限制导致诱变率增加。这些结果表明，缺铁导致月牙菇细胞遭受氧化应激并激活SOS反应，表明DNA损伤增加。
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.
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影响因子：
4.4
作者：
da Silva Neto JF;Lourenço RF;Marques MV
通讯作者：
Marques MV
影响因子：
3.2
作者：
Foreman, Robert;Fiebig, Aretha;Crosson, Sean
通讯作者：
Crosson, Sean
影响因子：
14.9
作者：
Galhardo, RS;Rocha, RP;Menck, CFM
通讯作者：
Menck, CFM
影响因子：
4.1
作者：
Garcia, Camila C. M.;Freitas, Florencio P.;Medeiros, Marisa H. G.
通讯作者：
Medeiros, Marisa H. G.
影响因子：
3.6
作者：
Baichoo, N;Wang, T;Helmann, JD
通讯作者：
Helmann, JD