[Mismatch repair in MNNG-induced genetically unstable monkey kidney vero cell]

Gel retardation analysis and in vitro DNA mismatch repair system were used to examine whether there were mismatch repair deficiency in MNNG-induced genetically unstable vero cell, which was manifested by a delayed and highly increased rate of non-targeted mutation. A mismatch binding protein which could selectively bind to G.T mispair in DNA was identified in its whole-cell extracts. It was also identified that G.T mispair could be specifically and effectively corrected into G.C pair in its nuclear extracts. Compared with normal vero cell, there were no functional deficiency of the above mismatch repair mechanisms. So it could be excluded the possibility that the functional deficiency of mismatch binding protein or G.T mismatch repair pathway participated in the induction of genetic instability in vero cell by MNNG.