Abstract: BACKGROUND & AIM: We applied a new SV40-based shuttle vector pSP189 and African Green kidney cells(Vero E6 cell line)，which constitute a shuttle vector /mammalian cell system to detect mutagenesis in vitro induced by animal drugs olaquindox. MATERIAL AND METHODS: The vector plasmids were induced by olaquindox , then were transfected into vero cells. After recovering from cells, the plasmids were transfacted into MBM7070 and selected mutant colonies. The mutation in 24 plasmids was determined by dideoxy sequence analysis. RESULTS: The lesion induced by 6.6µg•ml-1olaqiunxox included a large number of base substitutions, in addition to tandem base deletion. Point mutation frequencies for in vitro modified plasmids were dramatically increased over the spontaneous background lever, among which 70% of base substitutions happened on the site of G:C base pair, the predom in the mutation was G:C-T:A or G:C-A:T. Olaqiundox-induced mutations on the SupF shuttle vector did not distributed random, and had mutation hot spots (155bp) and sequence specificity, which were contained in the sequence 5’-NNTTNN-3’, mutation was easy appeared in N site, and tandem base deletion and rearrangement focused on ANGGCCNAAA sequence. CONCLUSION: Olaquindox induced the plasmid shuttle vector mutagenesis.

Key words: shuttle vector, olaquindox, mutagenesis, vero cells