Figure 1

Effect of polybrene in multiple virus infection. A549 cells were transduced with a 1:1 ratio of lentiviruses carrying EGFP or mCherry fluorescent gene. Lentivirus infection was performed by spin infection with centrifugation at 1100 × g for 30 min in the presence or absence of 8 μg/ml polybrene (MOI = 0.2 or 0.3). Twenty four hours later, the culture medium was replaced with fresh F-12 K medium with 2 μg/ml puromycin. After puromycin selection for 5 days, the proportion of cells with EGFP(+)/mCherry(−), EGFP(+)/mCherry(+) and EGFP (−)/mCherry(+) fluore-scence signals were analyzed by flow cytometry.