Expansion and Maintenance of Mouse Retinal Progenitor Cells

Mouse RPCs were isolated from dissociated retinas of post-natal (P4) C57BL/6J mice, homozygous for expression of enhanced green fluorescent protein under control of the beta actin promoter (EGFP+/+) (gift from Dr Young, Harvard University^{52 (link)}). RPCs were expanded and maintained at 37°C in a 5% CO₂ incubator in neurobasal complete medium (Invitrogen-Gibco, Rockville, MD) containing 2 mM l-glutamine, 100 mg/mL penicillin-streptomycin, B27 and N2 neural supplements, and 20 ng/mL epidermal growth factor (Promega, Madison, WI) as described previously by our group.^{11 (link),27 (link)} For testing, cells were detached with trypsin-EDTA, re-suspected in culture medium, counted, and seeded as described below.