[Expression of the amino acid operons in Escherichia coli strains with an altered transcription and translation apparatus. III. The effect of mutations in the rpoB gene coding for the beta-subunit of RNA-poly-merase on ilv-operon expression].

The influence of rifampicin resistance mutations on expression of the ilv operon of Escherichia coli was investigated. Some of these mutations, like those previously described in our works, occur in translation machinery of E. coli and inhibit derepression of the ilv operon. However, another group of mutations stimulated the expression of the operon when mutated cells were transferred from rich to minimal growth medium. The possible mechanisms of the effects of rifampicin resistance mutations on the action of coupled transcription--translation system are discussed.