Pathogenic Escherichia coli 4787 (O115:KV165) causes septicemia in pigs and expresses the fimbriae F1651 encoded by the foo operon that belongs to the P fimbrial family. fooI and fooB, encoding specific foo regulators, are divergently transcribed; their intergenic region is responsible for the regulation of foo expression. The role of global and local supercoiling (transcription-induced supercoiling within the intergenic region) on the regulation of foo expression was investigated. Expression of fooB was significantly altered when global negative supercoiling was reduced by a mutation that decreases DNA gyrase activity. Deletion of the topA gene, encoding for topoisomerase I that relaxes local negative supercoiling, further reduced fooB expression. This suggests that both global and local supercoiling can significantly affect fooB expression. Moreover, FooI, a positive regulator of fooB expression, has no effect on fooB expression in the topA null mutant. This study showed that divergent transcription from a strong promoter can significantly enhance fooB expression and compensate for the absence of FooI in a wild-type strain. © 2007 Federation of European Microbiological Societies.
CITATION STYLE
Tessier, M. C., Graveline, R., Crost, C., Desabrais, J. A., Martin, C., Drolet, M., & Harel, J. (2007). Effects of DNA supercoiling and topoisomerases on the expression of genes coding for F1651, a P-like fimbriae. FEMS Microbiology Letters, 277(1), 28–36. https://doi.org/10.1111/j.1574-6968.2007.00919.x
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