Grzesiuk E, Janion C
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw.
Mutat Res. 1993 Oct;297(3):313-21. doi: 10.1016/0165-1110(93)90022-f.
AB2497 and its mutS and umuDC derivatives were EMS-treated at the stationary phase and specificity of mutation measured. It was found that: (i) in mutS+ cells EMS induces predominantly GC-->AT transitions (by supB or supE(oc) formation) and in mutS- cells mainly AT-->TA transversions (by supL(NG) formation); (ii) transversions of AT-->TA are umuDC-dependent and mutational specificity is biased towards AT-->GC transitions in mutS- umuDC- strains. When mutS- umuDC- cells were transfected with plasmids bearing umuD'C or umuDC genes, mutational specificity was again biased towards AT-->TA transversions; (iii) experiments with bacteria bearing umuC::lacZ or recA::lacZ fusions suggest that processing of UmuD-->UmuD' might be poorer in EMS-treated mutS- than in mutS+ cells.
AB2497及其mutS和umuDC衍生物在稳定期经甲基磺酸乙酯（EMS）处理，并测定突变特异性。结果发现：（i）在mutS⁺细胞中，EMS主要诱导GC→AT转换（通过形成supB或supE(oc)），而在mutS⁻细胞中主要诱导AT→TA颠换（通过形成supL(NG)）；（ii）AT→TA颠换依赖于umuDC，并且在mutS⁻ umuDC⁻菌株中突变特异性偏向于AT→GC转换。当用携带umuD'C或umuDC基因的质粒转染mutS⁻ umuDC⁻细胞时，突变特异性再次偏向于AT→TA颠换；（iii）对携带umuC::lacZ或recA::lacZ融合基因的细菌进行的实验表明，经EMS处理的mutS⁻细胞中UmuD→UmuD'的加工可能比mutS⁺细胞中的差。
