Increased expression of Mg 2+ transport proteins enhances the survival of Salmonella enterica at high temperature
- 13 October 2009
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 106 (41), 17522-17527
- https://doi.org/10.1073/pnas.0906160106
Abstract
Mg(2+) homeostasis is important for Salmonella pathogenesis. In Salmonella enterica, the transcription of the mgtA gene, which encodes a Mg(2+) transporter, is regulated by a Mg(2+)-sensing riboswitch [Cromie MJ, Shi Y, Latifi T, Groisman EA (2006) Cell 125:71-84]. In a genetic analysis of the determinants of thermotolerance in S. enterica serovar Typhimurium, we isolated the chr-1 mutation that increased the resistance of exponential phase cells to killing by high temperature. This mutation is a single base change in the mgtA riboswitch that causes high-level constitutive expression of mgtA. We showed that another mgtA riboswitch mutation, DeltaUTR(re-100), which had been constructed by Cromie et al., also confers similar increased thermotolerance. Surprisingly, the chr-1 mutation is located at a position that would not be predicted to be important for the regulatory function of the riboswitch. We obtained physiological evidence suggesting that the chr-1 mutation increases the cytosolic free Mg(2+) concentration. High-level expression of the heterologous MgtE Mg(2+) transport protein of Bacillus subtilis also enhanced the thermotolerance of S. enterica. We hypothesize that increased Mg(2+) accumulation might enhance thermotolerance by protecting the integrity of proteins or membranes, by mitigating oxidative damage or acting as an inducer of thermoprotective functions.This publication has 46 references indexed in Scilit:
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