tokens: Abrogation of p53 function by E6 resulted in an increase in the spontaneous mutation frequencies at the heterozygous thymidine kinase ( TK ) locus but not at the hemizygous hypoxanthine phosphoribosyl transferase ( HPRT ) locus .
folded_tokens: abrogation of p53 function by e6 result in a increase in the spontaneous mutation frequency at the heterozygous thymidine kinase ( tk ) locus but not at the hemizygous hypoxanthine phosphoribosyl transferase ( hprt ) locus .