Figure 1. Lentivirus transduction of retinal progenitor cells. A: Schematic representation of feline immunodeficiency virus (FIV) vector. Abbreviations are: LTR, FIV long-terminal repeat; CMV, human cytomegalovirus promoter, and YFP, yellow fluorescent protein. B: In vitro live fluorescence image of retinal progenitor cells (RPCs) spheres for yellow fluorescent protein (YFP) expression (top, fluorescence field; bottom, bright field). RPCs were transduced with FIV-YFP and analyzed for YFP expression at day 8 post-transduction with an Olympus IX50 inverted fluorescence microscope. C: Flow cytometry analysis of YFP expression in RPCs. Flow cytometric histogram of control cells (filled gray histogram) and FIV-YFP transduced cells (open black line) from representative experiment is shown. At least 5,000 gated cells were analyzed for YFP expression. The majority of FIV-transduced RPCs (97.5%) were YFP positive.