GFP expression linked directly to the Oct4 promoter. A GFP Neomycin construct was added to the H1 cell line via homologous recombination and targeted to the POUF1 gene. Cells will express GFP when Oct4 is expressed （e.g. undifferentiated state）. Oct4/GFP positive cells are selectable using Neomycin. These cells tend to differentiate more frequently and are best grown in slightly sparser conditions. It is not unusual to have to manually remove differentiation at each passage in the absence of selection.
