Regulated OmpF porin synthesis in Escherichia coli K-12

Abstract The effects of growth conditions on the expression of the Escherichia coli K-12 major outer membrane porin gene ompF were determined by measuring the amount of OmpF protein incorporated into the outer membrane, β-galactosidase activity in cells in which lacZ was regulated by the ompF promoter, and by studying their effects in the presence of the general transcription inhibitor rifampicin. A variety of conditions reduced ompF transcription. Common features among the inhibitors of ompF expression could not be identified; another protease inhibitor and another uncoupler did not specifically affect ompF expression. It is therefore concluded that the inhibitors interact directly or indirectly with a sensory system (possibly EnvZ protein) which affects the porin gene regulon accordingly.