Combined use of flow cytometry and G418 to screen the recombinant plasmid transfected cells

Objective To optimize the selective method to obtain the pure recombinant plasmid transfected U937 cells. Methods pRNAT U6.1/Neo plasmid containing both Neor and GEP genes was selected. After the plasmids had been transfected into U937 cells, the purity of the transfected cells, selected by G418 only or by both G418 and flow cytometer (FCM), was compared. Results The highest purity of GFP positive cells was 72.0% when selected by G418 only; however, the purity of GFP positive cells was always above 90.0% while using both G418 and FCM method. Conclusions It is a highly effective method to select the transfected cells using both G418 and FCM.