TETRAHYMENA BIFUNCTIONAL DIHYDROFOLATE REDUCTASE - THYMIDYLATE SYNTHASE DEFICIENCY AND ITS USE

摘要

A method for producing a ciliate cell with reduced or essentially no dihydrofolate reductase (DHFS) activity or reduced or essentially no thymidylate synthase (TS) activity or both reduced or essentially no dihydrofolate reductase and thymidylate synthase (DHFR-TS) activity is claimed, comprising the steps of a) transforming ciliate cells by inserting a construct containing an allele altering the gene encoding the endogenous DHFR-TS into at least one of the endogenous DHFR-TS genes of the ciliate macronucleus (MAC), b) inducing an allelic assortment process in the transformed ciliate cells to generate cells having the construct inserted in most or all functional DHFR-TS genes of the MAC, and c) identifying the cells generated in step b) by cultivation with or without thymidine.