Selection of highly transfectable variant from mouse mastocytoma P815

Abstract

A tk⁻ cell line derived from mouse mastocytoma P815 was transfected with a plasmid carrying a thymidine kinase gene. The tk⁺ cells were obtained at a frequency of 10⁻⁶. From some of these tk⁺ transfectants it was possible to select tk⁻ cells with BrdU so that these cells could be submitted again to transfection with the thymidine kinase gene. By repeating cycles of transfection and tk⁺ selection followed by reverse selection with BrdU, it was possible to obtain a stable variant having a 100-fold increase in transfection efficiency. This HTR (high transfection) variant shows a high efficiency of transfection (10⁻⁴) for the neomycin-resistance gene as well as for the thymidine kinase gene.