Immunofluorescence images of postnatal mouse retina stained with antibodies to NP1 (first column), NP2 (second column), or NPR (third column) at P5, P7, or P14. A–I, WT retinas. J–L, NP1/2/R KO retinas. In WT retinas (A–I), NP1-, NP2-, and NPR-immunopositive cells are seen in the ganglion cell layer at every age examined. No specific signal is seen in the retinas of NP1/2/R KO mice (J–L). IPL, Inner plexiform layer; GCL, ganglion cell layer. Scale bar, 50 μm.