Selective loss of cone function in mice lacking the cyclic nucleotide-gated channel CNG3

Two types of photoreceptors, rods and cones, coexist in the vertebrate reti na. An in-depth analysis of the retinal circuitry that transmits rod and co ne signals has been hampered by the presence of intimate physical and funct ional connections between rod and cone pathways. By deleting the cyclic nuc leotide-gated channel CNG3 we have generated a mouse lacking any cone-media ted photoresponse. In contrast, the rod pathway is completely intact in CNG 3-deficient mice. The functional loss of cone function correlates with a pr ogressive degeneration of cone photoreceptors but not of other retinal cell types. CNG3-deficient mice provide an animal model to dissect unequivocall y the contribution of rod and cone pathways for normal retinal function.