Electric field mediated transformation: Isolation and characterization of a TK+ subclone

Abstract Transformation of mammalian TK − cells by a plasmid carrying the TK gene from Herpes virus simplex 1 (pAGO) was mediated by electroporation. The cells were treated either in suspension or growing in monolayers directly in the petri dish. The yield of transformation was between 8.10 −5 and 2.10 −4 per μg DNA depending on the experimental conditions. The structure of the integrated DNA was investigated proving the occurence of a duplication process that affected preferentially the pBR322 part of the pAGO DNA (60 copies per cell). The TK gene that gave the TK + phenotype to the selected clone was present in less than 6 copies.