在MNNG诱发的延迟发生的,以非定标性突变形成为特征的遗传不稳定vero细胞抽提物中,应用凝胶阻滞和体外错配修复技术,发现仍存在特异性针对G·T的错配结合蛋白,能选择性识别并结合DNA中的G·T错配;同时发现在该细胞核抽提物中G·T错配能被有效、特异地修复成G·C。经与正常vero细胞比较,证实二者功能均无缺陷。从而排除了MNNG通过对错配结合蛋白及G·T错配修复功能的损伤而诱发细胞遗传不稳定的可能机制。 In MNNG-induced delayed instability vero cell extracts characterized by non-scal- able mutations, gel retardation and in vitro mismatch repair techniques were used and found to be specific for G · T The mismatch binding protein can selectively recognize and bind to G · T mismatch in DNA. At the same time, G · T mismatch can be effectively and specifically repaired to G · C in this nuclear extract. Compared with the normal vero cells, confirmed that both functions are not defective. Thus eliminating the possible mechanism of MNNG inducing cell genetic instability through damage to mismatch binding protein and G · T mismatch repair function.