In electro-phoretic mobility-shift assays , Fis was found to bind to both gyrB promoters of S. enterica , despite the strong divergence from the E. coli sequence on the part of the former .
Fis also binds to and represses the promoters of the gyrB genes in both E. coli and S. Typhimurium , resulting in reduced levels of DNA supercoiling .
In E. coli , FIS binds the gyrB promoters to repress their expression ; similarly , FIS has been found to repress S. enterica gyrB .
Therefore the observed differences in FIS control of DNA supercoiling suggested that the role of FIS in the regulation of gyrB might differ between the two species .
Therefore the observed differences in FIS control of DNA supercoiling suggested that the role of FIS in the regulation of gyrB might differ between the two species .
FIS control of gyrB .