Complete cDNA sequences of mouse rod photoreceptor cGMP phosphodiesterase α‐ and β‐subunits, and identification of β′‐, a putative β‐subunit isozyme produced by alternative splicing of the β‐subunit gene

Abstract

We have characterized overlapping cDNA clones encoding cGMP phosphodiesterase (PDE) α‐ and β‐subunits of mouse retinal rod photoreceptors. The open reading frames predict an α‐subunit of 100 kDa (856 residues), and a β‐subunit of 99 kDa (853 residues). Sequence analysis of two of twelve β‐subunit clones predicts the presence in the retina of an additional PDE, termed β, which is generated by alternative splicing of the β‐subunit gene, β differs from β only at the C‐terminus being 55 residues shorter and lacking the Caax motif found at the C‐termini of both the α‐ and β‐subunits. A 300 residue segment thought to contain the active site is present in the C‐terminal half of α, β and β.