Transcription of E. coli topA is driven by the interplay of at least four transcription start sites , allowing FIS to be both a repressor of E. coli topA expression .
Although topA promoter function has routinely been studied using plasmid-based systems , our results indicate that in E. coli the expression of plasmid-borne PtopAEc is enhanced by FIS whereas the chromosomal copy of the promoter is repressed by FIS -LRB- compare 4A -RRB- .
Although topA promoter function has routinely been studied using plasmid-based systems , our results indicate that in E. coli the expression of plasmid-borne PtopAEc is enhanced by FIS whereas the chromosomal copy of the promoter is repressed by FIS -LRB- compare Figs 3A -RRB- .