The nucleotides within exon 20 encoding for 14 amino acids in the calmodulin binding domain were removed and a floxed neo cassette was inserted into intron 19 via homologous recombination. Cre mediated recombination removed the neo cassette. Western blot analysis did not detect a change in the level of protein expression in the retinas of homozygous mice compared to wild-type controls. The mutant protein is located in the outer rod segments similar to the wild-type protein. (J:166744)