Efficient transformation of mammalian cells with constructs containing a puromycin-resistance marker

Recombinant plasmids have been obtained that lead to the accumulation of five- to ten-fold more puromycin-N-acetyl-transferase (PAC) mRNA and two- to three-fold more PAC activity than the already described plasmid pSV2pac [Vara et al., Nucl. Acids Res. 14 (1986) 4117-4124]. When these optimized recombinants were used for stable transformation to puromycin resistance, efficiencies up to 1 x 10(-2) were obtained, indicating that these pac-containing recombinants may be very useful dominant selectable markers for gene transfer in mammalian cells.