Cloning and sequencing of the gamma-subunit of retinal cyclic-GMP phosphodiesterase from rd mouse.

Molecular cloning, sequencing and Northern blot analysis have been performed on the gamma-subunit of cyclic-GMP phosphodiesterase (cGMP-PDE gamma) from the retina of mice affected with the rd mutation. The full length cDNA has a total of 926 bp which include 261 bp of coding region, 121 bp of 5'-untranslated and 544 bp of 3'-untranslated regions. The latter contains a poly A tail of 50 bp. The coding region has only one base changed from the normal mouse cGMP-PDE gamma cDNA, a C replaced by an A at position 105 (Tuteja and Farber, 1988), and 91% homology with the coding region of the bovine retinal enzyme (Ovchinnikov et al., 1986). The mRNA of cGMP-PDE gamma is 900 bp long in both normal and rd mouse retinas and codes for a protein containing 87 amino acids. The deduced amino acid sequence of cGMP-PDE gamma from rd retina has 100% homology with that of the enzyme from normal mouse retina and 97.7% homology with that of the bovine cGMP-PDE gamma suggesting that if this subunit of cGMP-PDE is properly transcribed and translated, it is not defective in the degenerative rd mouse retina.