We are engineering adeno associated viruses (AAV) to target specific cell types in the retina. We have developed cell-specific AAV vectors can transfer gene constructs specifically to rods, cones, Mller glia or RPE cells in the eye. This figure shows expression of the green fluorescent reporter protein gfp exclusively in a blue?wavelength sensitive cone in monkey retina. We plan to use these targeted vectors for gene replacement therapy for recessive eye diseases. Genetically dominant eye diseases are gain-of-function mutations and cannot be corrected by adding a corrective gene. For these studies, mutation-specific, therapeutic strategies are being developed to 'knock-down' the mRNA from the mutant allele by expression of ribozymes in AAV.