Figure 4. HESC-derived RPE cells express molecules required for POS specific phagocytosis. A: RT–PCR analysis of gene expression in HESC-derived RPE cells (HESC-RPE), control nonpigmented HESC (HESC-Control) and the human RPE cell line ARPE-19. cDNA was synthesized from 3 μg of RNA in a 20 μl reaction, from which 1 μl was used for PCR amplification. Lanes to the right of each sample are genomic DNA control reactions, which lacked the reverse transcriptase during cDNA synthesis. NTC is a no RNA template sample to control for non-specific amplification. All PCR reaction products were resolved by agarose gel electrophoresis. PCR primer sequences, amplicon size, and melting temperatures are described in Table 1. Tbp was amplified in all samples as a housekeeping control gene. B: western blot analysis of protein expression in HESC-P, HESC-NP and ARPE-19 cells. Equal amounts of protein were resolved on an SDS–PAGE gel, transferred onto membranes, and hybridized with antibodies for MERTK (180 kDa), focal adhesion kinase (FAK, 125 kDa), αV integrin (125–135 kDa), and β5 integrin (100 kDa). Membranes were stripped and re-probed with GAPDH (36 kDa) as a loading control.