The mouse model. (a) Mutation analysis by direct sequencing revealed that the homozygous mouse harbored a missense mutation at aa residue 229, causing an amino acid change from Phe to Ser. The highlighted nucleotide indicates the mutation in the mouse (left). RPE65 protein is an evolutionarily conserved protein, and F229 is a nearly invariant residue from human to zebra fish (right). (b) Retinal morphology at 1 and 4 months and 1 year of age was analyzed by light microscopy. ONL thinning was progressive, and IS/OS was shorter than controls at all ages examined. OSs: outer segments, ISs: inner segments, ONL: outer nuclear layer, OPL: outer plexiform layer, INL: inner nuclear layer. Scale bar 20 m. (c, d) Physiological retinal function was analyzed by ERG at 4 weeks (c) and 17 weeks of age (d). The plotted amplitude was obtained at 9 weeks from control and mice (c) or at 17 weeks from control and from homozygous mice. = 3.
