The feedback response of Escherichia coli rRNA synthesis is not identical to the mechanism of growth rate-dependent control

Growth rate-independent rrn P1 promoter mutants were tested for their abili ty to respond to changes in rrn gene dosage. Most were found to be normal f or the feedback response. In addition, cellular Levels of the initiating nu cleoside triphosphates remained unchanged when the rrn gene dosage was alte red. These results suggest that the feedback response cannot be the mechani sm for growth rate-dependent control of rRNA synthesis and that the relatio nship between these two processes mag be more complicated than is currently understood.