BMH 71-18 mutS and ES1301 mutS are mismatch repair minus E. colistrains. Use of these strains prevents repair of the newly synthesized unmethylated strand, leading to high mutation efficiencies. Both ES1301 and BMH 71-18 mutS are recA+, therefore inserts containing highly repetitive sequences may be unstable. ES1301 is Tets for cycling between antibiotic resistances. BMH 71-18 is Tetr; therefore, it can only be used to select Ampr or CATr mutants.
ES1301 mutS Genotype: lacZ53, mutS201::Tn5, thyA36, rha-5, metB1, deoC, IN(rrnD–rrnE).
BMH 71-18 mutS Genotype: thi, supE, Δ(lac-proAB), [mutS::Tn10], [F´, proAB, lacIqZΔM15].
- Wallace, R.B. et al. (1981) Gene 16, 21–6.