Evaluate the capacity and efficiency of isolated cone photoreceptor precursors to migrate and integrate into outer nuclear layer of retina, after sub-retinal transplantation.

We used a novel GFP-reporter mouse line with a gene trap insertion into the Coiled-coil domain containing 136 (Ccdc136)/ nasopharyngeal carcinoma-associated gene 6 (NAG6) locus. In the Ccdc136GFP mouse, reporter gene expression from the Ccdc136GFP allele is initiated in embryonic cone precursors (E13) located at the apical surface of the retina and in the adult retina it marks S-cones and rod bipolar cells. By flow-cytometry assisted cell sorting at E17, we isolated trypsin dissociated cone precursors, to yield 10,000/µl cell suspension. Then about 1.5 µl per eye (15,000 cells) was transplanted into sub-retinal space of adult wildtype C57Bl/6 mice.

Three weeks post transplantation we observed integrated GFP+ cells in the ONL and several examples of GFP+ cells with apical and basal processes and the number of integrated cells ranged from 140 to 270 per eye, representing approximately 1% of injected cells.

These results show that this reporter line can be used for prospective enrichment of endogenous cones and that these cones can integrate into wildtype adult recipients, efficiently.