Green Fluorescent Protein as a Transcriptional Reporter in Epithelial Cells: Real-Time Studies of the Human Involucrin Promoter

Green Fluorescent Protein (GFP) is a popular reporter for numerous uses in mammalian cells because its activity can be measured directly without cofactors or reagents. We show that an improved GFP variant, the cycle-three GFP gene in the pGlow-TOPO® vector is useful as a reporter of mammalian promoter activity. The 5´ regulatory region from the human involucrin gene was cloned upstream of the cycle-three GFP gene and the resultant constructs transfected into C33-A epithelial tumor cells and normal keratinocytes. Fluorescence analysis whole cells showed that cyclethree GFP in pGlow-TOPO® is reliable for reporting mammalian promoter function under different conditions. GFP activity was comparable to that of CAT, indicating that this method can be used in transcriptional studies for numerous mammalian promoters.