Figure 7

Nr2e1 ^frc/frc S-cones were overrepresented in Wt↔frc chimeras. Transverse retinal sections from P7 Nr2e1 ^+/+, Nr2e1 ^frc/frc, and chimeric mice were immunostained for S opsin (S-cones). a Retinal sections showing S-cones labeled with S Opsin (red). b To assess differences in S-cones numbers between wild-type and Nr2e1-mutant retinas, S opsin positive cells were counted throughout five sections across the retina of P7 Nr2e1 ^+/+ and Nr2e1 ^frc/frc mice. Numbers were normalized to retinal length and expressed as percentages of Nr2e1 ^+/+ cell numbers. There was no significant difference between the numbers of S opsin positive cells in wild-type and Nr2e1-mutant retinas. c Retinal sections of chimeras showing S opsin in red. The density of Nr2e1 ^frc/frc S opsin positive cells appeared higher in Nr2e1-mutant regions (EGFP positive) compared to wild-type regions. The arrows show a region with Nr2e1-mutant cells and a high density of S-cones. Representative images of a 50 % Wt↔Wt and a 39 % Wt↔frc chimeric retina are shown. d Quantification of the density of S-cone cells that were derived from host blastocyst or ESCs in chimeras was assessed by counting single-labeled cells (S opsin positive and EGFP negative) or double-labeled cells (S opsin positive and EGFP positive) and dividing them by the EGFP negative or EGFP positive retinal area (ONL + INL), respectively. In Wt↔Wt chimeras, the density of EGFP positive and EGFP negative S-cone cells was similar while in Wt↔frc chimeras the density of Nr2e1 ^frc/frc S-cone cells (EGFP positive) was higher (48 % increase) than the density of wild-type S-cone cells (EGFP negative). n = 3 for Nr2e1 ^+/+, n = 3 for Nr2e1 ^frc/frc, n = 3 for Wt↔Wt, n = 3 for Wt↔frc; *, P ≤ 0.05; neg., negative;ns, not significant; error bars represent SEM. GCL, ganglion cell layer; Hoechst, nuclear counterstain (blue); INL, inner nuclear layer; ONL, outer nuclear layer; pos., positive; scale bar = 50 μm