[Mutations of resistance to rifampicin leading to increased activity of the uridine phosphorylase gene in Escherichia coli].

A number of rifampicin resistance mutations which have been mapped in the region of the rpoB gene, cause an increase in the activity level of a catabolite sensitive uridine phosphorylase (udp) gene. This effect is observed in bacterial cells deficient for the active protein repressor cytR, controlling expression of the udp gene. In cytR mutant cells grown on the medium containing glucose, the level of uridine phosphorylase is further increased by a factor of 1,5 to 2 under the influence of rif-r mutations. Concomitantly, the activity of some other catabolite sensitive genes controlled by the cytR protein is also increased on the medium with glucose. The data obtained suggest that the RNA polymerase beta-subunit participates in regulation of some catabolite sensitive genes.