TTR and infection: At Multiplicity of Infection (MOI) of 1, in cultured RH and RNT cells, the percentage of GFP positive cells was similar to those transduced with a lentiviral vector containing a ubiquitously expressed promoter, the phosphoglycerate kinase 1 (PGK1) promoter (respectively 76% and 91% for TTR, 69% and 83% for PGK1), confirming the hepatocytic origin of these cells (Figure 5).