Mammalian cell culture and G418 selection - (Jul/16/2013 )

I am working with guinea pig fibroblasts, epithelial, and endothelial cells using 400-600ug/mL G418 for selecting cells with my GOI (GFP or mCherry tagged).

I had a general question regarding the neo-resistant gene - our transfected mammalian cells that took our GOI have the neo-resistant gene, and we see some dying off and some surviving during the selection process. However we also see mammalian cells dying / surviving as well. If the mammalian cells do not have the neo-resistant gene how are they surviving>? Did they take up the plasmid and express the SV40 but not the CMV promoter?

You asked the same question yesterday and the user leelee replied to it. Did you read her reply?