RT Journal Article SR Electronic(1) A1 Bielińska, Anna A1 Hulanicka, DanutaYR 1986 T1 Effect of DNA Gyrase Inhibitors and Urea on the Expression of cysB, the Regulatory Gene of the Cysteine Regulon JF Microbiology, VO 132 IS 9 SP 2571 OP 2576 DO https://doi.org/10.1099/00221287-132-9-2571 PB Microbiology Society, SN 1465-2080, AB Summary: cysB, the regulatory gene of the cysteine regulon, is autoregulated. Inhibitors of both gyrase subunits, nalidixic acid and novobiocin, affect the expression of cysB, as monitored by β-galactosidase activity in cysB:: lac fusion strains. In gyrA mutants that are resistant to nalidixic acid, this drug does not affect cysB expression. The amount of mRNA transcribed from the cysB promoter isolated from cultures grown in the presence of gyrase inhibitors was significantly lower than that from the control culture without inhibitors. Urea also decreased cysB expression. These results suggest that DNA topology could play a role in cysB expression., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-132-9-2571