Characterization of Human and Mouse Rod cGMP Phosphodiesterase δ Subunit (PDE6D) and Chromosomal Localization of the Human Gene

Abstract

The mammalian multisubunit photoreceptor cGMP phosphodiesterase PDEαβγ2(PDE6 family) is a peripherally membrane-associated enzyme. A novel subunit, termed PDEδ (HGMW-approved symbol, PDE6D; MW 17 kDa), is able to detach PDE partially from bovine rod outer segment membranes under physiological conditions. Cloning of human and mouse PDEδ cDNAs revealed that PDEδ is a nearly perfectly conserved polypeptide of 150 amino acids that shows partial sequence homology to photoreceptor RG4 of unknown function. Multiple-species Southern blot analysis demonstrates that the PDEδ gene has been well conserved during evolution and is detectable at high stringency in invertebrates. The human and mouse genes are contained in less than 8 kb of genomic DNA and consist of four exons and three introns (0.7–4 kb in human, 0.7–2.2 kb in mouse). The PDEδ gene structure is identical to that of the C27H5.1 gene identified in the eyeless nematodeCaenorhabditis elegans.The human PDEδ gene (locus designation PDE6D) was localized to the long arm of chromosome 2 (2q35–q36) by fluorescencein situhybridization. By synteny, the mouse PDEδ gene is predicted to reside on chromosome 1.