Stable Expression of hrGFP by Mouse Embryonic Stem Cells: Promoter Activity in the Undifferentiated State and During Dopaminergic Neural Differentiation

Abstract

Three promoters, cellular polypeptide chain elonga- tion factor 1 alpha (EF1), cytomegalovirus (CMV), and Rous sarcoma virus (RSV) were examined for stable transgene expression in mouse embryonic stem (ES) cells and their progeny during dopaminergic neural dif- ferentiation. In undifferentiated ES cells the EF1 pro- moter was highly effective, while CMV had moderate activity. After 3 months in culture, expression of human- ized renilla green fluorescent protein (hrGFP) was unchanged for the EF1 promoter and decreased for CMV. At the nestin-positive stage of differentiation, hrGFP and nestin were colocalized in about 20% of cells for EF1, in contrast to 80% of cells for the CMV pro- moter. In tyrosine hydroxylase (TH)-positive neurons neither the EF1 nor CMV promoter were effective. The RSV promoter was inactive in undifferentiated, nestin- positive, and TH-positive cells. Thus, EF1 and CMV are effective promoters for transgene expression in undiffer- entiated ES cells and nestin-positive neural precursors. Stem Cells