FIS IS A REGULATOR OF METABOLISM IN ESCHERICHIA-COLI

The Escherichia coli DNA-binding protein FIS (factor for inversion sti mulation) stimulates site-specific recombination reactions catalysed b y DNA invertases and is an activator of stable RNA synthesis. To addre ss the question of whether FIS is involved in other cellular processes we have identified and sequenced proteins whose expression pattern is affected by FIS. This has led to the identification of several E. col i genes whose expression in vivo is either enhanced or repressed by FI S. All of these genes encode enzymes or transport proteins involved in the catabolism of sugars or nucleic acids, and their expression is al so dependent on the cAMP-CRP complex. In most cases studied the regula tion by FIS is indirect and occurs through effects on the synthesis of the respective repressor proteins. We conclude that FIS is a transcri ptional modulator involved in the regulation of metabolism in E. coli.