The puromycin-resistance gene (puro) was cloned into pCDH-EF1-MCS-T2A-copGFP (A) and pCDH-MCS-T2A-copGFP-MSCV (B); and the copGFP gene (cG) was cloned into pCDH-EF1-MCS-T2A-Puro (C) and pCDH-MCS-T2A-Puro-MSCV (D). The resulting dual reporter constructs were packaged into pseudoviral particles followed by transduction into HT1080 cells. All constructs were also puromycin resistant (data not shown)