Visinin: biochemical and molecular comparisons in normal and rd chick retina

Western, northern and DNA sequence analyses were used to determine if the retinal protein, visinin, is defective in the chicken retinal degeneration mutant, rd. A 22kDa band, corresponding to purified visinin, was stained with equal intensity on Western blots of +/+, +/rd and rd/rd retinal protein probed with a visinin polyclonal antibody. Hybridization of a northern blot of +/+, +/rd and rd/rd poly(A)+ RNA with a random-primer labelled visinin cDNA probe showed a single, equally labelled 1-Kbp band in each of the samples. Finally, no differences were found between the nucleic acid sequences of the 579 bp cDNAs encoding +/+ and rd/rd visinin. We did, however, find one significant difference between our visinin DNA sequence and the previously published chick visinin DNA sequence. We consistently observed a C at position 118 rather than the published T which changes the amino acid residue at position 40 from serine to proline. Based on the results of this study, we conclude that visinin is not defective in the rd chick model of hereditary retinal degeneration.