Abstract: Purpose: To develop a method of t k gene mutation assay in WTK1 cell for testing gene mutation induced by chemical mutagens. Methods: t k locus mutation frequency and p53 gene protein expression level were detected after WTK1 lymphoblastoid cells were treated with methyl methanesulfonate (MMS). Results: MMS induced t k locus mutation with mutation frequency 3～10 times higher than that of spontaneous mutation frequency of WTK1 cell. Induction mutation frequency depended on dose level. t k gene mutation frequency (MF) was 985.2 / 10 6 cells at 10 mg•L-1. There were two different phenotypes of mutation colonies, namely t k-NG and t k-SG mutant colonies, but mainly t k-SG mutant colonies. The level of P53 protein expression increased after treatment of WTK1 cell with MMS. Conclusion: MMS inducted t k locus mutation in WTK1 human diploid lymphoblastoid cell, and WTK1 cell can be used in mutagenesis test at t k locus.

Key words: WTK1 cell, thymidine kinase(t k) gene, mutation, methyl methanesulfonate(MMS)