Hi,

I have been trying for the longest time to transfect my flag tagged or GFP tagged GPCRs into mouse embyronic stem cell (E14), with little sucess. I tried transient transfection with lipofectamine and Amaxa, lentiviral vector, and stables. The transient trasnfectants quickly disappear and the expression in the stable is barely above the background (2x above background, as determined by FLAG ELISA or GFP detection by flow cytometry). Since it's embryonic stem cells, I really hate to passage the mouse embryonic stem cells too long. Does any one have any experience with gene expression in mouse embyronic stem cell? Any insight will be greatly appreciated.