In four separate experiments, we added either 100 nM pTAT-mcMyc or pTAT control protein to duplicate wells of OSK-expressing MEF daily for 12 days and compared Oct4-GFP+ colony counts to OSK-expressing MEF at days 5, 7, 9, and 12 after infection (n = 4; Figure 2(d)). Here, POU5F1 is linked to infection.