In vivo enhancement of general and specific transcription in Escherichia coli by DNA gyrase activity

Enhancement of ribosomal ribonucleic acid synthesis by deoxyribonucleic acid gyrase activity in Escherichia coli

“…mRNA synthesis is only partly inhibited by DNA gyrase inhibitors. These findings are in agreement with other reports that protein syn- thesis is only moderately affected (17) and only a subset of mRNA species is inhibited (5,7,15,23,25,28), whereas some mRNA's are stimulated (17,23). Conflicting results were reported by Wahle and Mueller, who found that mRNA synthesis was more inhibited by DNA gyrase inhibitors than rRNA synthesis (31).…”

“…DNA gyrase inhibitors strongly reduce the transcription of rRNA operons (18,34), the lactose operon, and the colicin El gene, whereas other genes are not affected (34). Also in vivo, DNA gyrase inhibitors block the synthesis of a subset of mRNA species (5,15,17,23,28). Previously, we have demonstrated that the B-subunit inhibitor novobiocin strongly inhibits rRNA synthesis, whereas mRNA synthesis is only moderately affected (18).…”

DNA Topoisomerases: Enzymes That Control DNA Conformation

“…Evidence for this conclusion is based on the observation of sequential cessation of transcription in a polycistronic operon (trp) after addition of a gyrase inhibitor (oxolinic acid). Analysis of the polycistronic mRNA made after addition of the drug showed that promoterproximal cistrons disappeared earlier than promoter-distant ones (KUBO et al 1979). Further evidence for a role of gyrase in initiation was derived from in vitro transcription of ColE1 DNA.…”

Effect of temporary inhibition of DNA gyrase activity on synchronous cell division in Escherichia coli B/r.

“…For example, cells growing in the presence of NAL could accumulate division proteins (20)(21)(22)(23) or be affected in the generalised or specific transcription of various genes (23)(24)(25). To test this possibility, synchronous cultures were simultaneously treated with NAL and chloramphenicol (150 ,ug/ml, final concentration).…”