Temperature Dependent Control of the R27 Conjugative Plasmid Genes
Conjugation of R27 plasmid is thermoregulated, being promoted at 25°C and repressed at 37°C. Previous studies identified plasmid-encoded regulators, HtdA, TrhR and TrhY, that control expression of conjugation-related genes (tra). Moreover, the nucleoid-associated protein H-NS represses conjugation at non-permissive temperature. A transcriptomic approach has been used to characterize the effect of temperature on the expression of the 205 R27 genes. Many of the 35 tra genes, directly involved in plasmid-conjugation, were upregulated at 25°C. However, the majority of the non-tra R27 genes—many of them with unknown function—were more actively expressed at 37°C. The role of HtdA, a regulator that causes repression of the R27 conjugation by counteracting TrhR/TrhY mediated activation of tra genes, has been investigated. Most of the R27 genes are severely derepressed at 25°C in an htdA mutant, suggesting that HtdA is involved also in the repression of R27 genes other than the tra genes. Interestingly, the effect of htdA mutation was abolished at non-permissive temperature, indicating that the HtdA-TrhR/TrhY regulatory circuit mediates the environmental regulation of R27 gene expression. The role of H-NS in the proposed model is discussed.
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REFERENCES
- https://doi.org//10.1111/j.1365-2958.2008.06115.x
- https://doi.org//10.1099/mic.0.28256-0
- https://doi.org//10.1038/sj.bjp.0707607
- https://doi.org//10.1128/mBio.01442-14
- https://doi.org//10.1128/JB.187.24.8267-8277.2005
- https://doi.org//10.1128/JB.187.12.3950-3959.2005
- https://doi.org//10.1016/j.plasmid.2013.01.009
- https://doi.org//10.1111/mmi.12823
- https://doi.org//10.1111/1462-2920.13579
- https://doi.org//10.1007/BF00272087
- https://doi.org//10.1101/SQB.1981.045.01.022
- https://doi.org//10.1371/journal.pntd.0001245
- https://doi.org//10.1128/JB.184.8.2173-2180.2002
- https://doi.org//10.1128/JB.185.2.581-591.2003