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| Keywords: Dnanegativesupercoiling.jpg Uploaded with en wp UW marker 2012 12 10 dna negative supercoiling with fis http //www sciencedirect com/science/article/pii/S0065216408010022 Charles J Dorman http //www sciencedirect com/science/article/pii/S0065216408010022 Charles J Dorman The Fis protein influences DNA supercoiling at a global level The dimeric Fis protein represses the promoter of its own gene fis and those of the genes coding for the GyrA gyrA and GyrB gyrB subunits of the heterotetrameric DNA gyrase Fis has a more complicated relationship with the gene coding for the monomeric DNA topoisomerase I topA ; here Fis acts positively when present at low concentrations but is a repressor at high concentrations This dual input is indicated by the +/ ˆ’ symbol at the topA promoter The angled arrows upstream of each gene represent transcription start sites The Fis protein also binds to the chromosomal DNA where it can influence its availability as a substrate for DNA gyrase and DNA topoisomerase I Thus Fis can influence the homeostatic control of global DNA supercoiling by modulating the expression of the genes coding for the main topoisomerases and by modulating their activities on the DNA substrate Uncategorized 2014 August 29 | ||||
