Transcription-coupled repair promotes mutagenesis. (A) Median rifampicin concentration that allows for growth in the indicated strains at the indicated timepoints. n = 23 (wt), 36 (ΔuvrA), 24 (Δmfd), 12 (ΔuvrA Δmfd) biological replicates. (B) Mutation rates of B. subtilis strains measured using rifampicin. n = 54 (wt), 48 (ΔuvrA), 37 (ΔuvrB), 47 (ΔuvrB + uvrB), 48 (ΔuvrC), 59 (Δmfd), 49 (Δmfd + mfd), 40 (Δmfd ΔuvrA), 40 (Δmfd ΔuvrB), 50 (Δmfd ΔuvrC) biological replicates. Statistical significance was assessed with a two-tailed Mann–Whitney U test, *P < 0.05. Error bars are 95% CI.