RESUMO
cDNA clones encoding the beta-subunit of the photoreceptor cGMP phosphodiesterase (PDE) were isolated from a human retina library and their sequence was determined. The encoded polypeptide consists of 854 amino acid residues with a calculated molecular mass of 98,416 Da. Alignment of the deduced amino acid sequence with the earlier analysed alpha-, beta- and alpha'-subunits of bovine and mouse PDEs demonstrates a high homology. Two overlapping recombinant lambda phage clones containing 26 kb of the human PDE beta-subunit gene were isolated from the genomic library. A total nucleotide sequence of exons 4-22 of the PDE beta-subunit gene was established which completely corresponded to the cDNA structure. According to sequence analysis no potential possibility for alternative splicing of the beta-subunit gene was observed between exons 20 and 21 which led to the formation of the beta'-subunit as described for mouse PDE. Polymerase chain reaction (PCR) experiments also confirm the absence of the PDE beta'-subunit in human retina.
Assuntos
3',5'-GMP Cíclico Fosfodiesterases/genética , DNA , Diester Fosfórico Hidrolases , Células Fotorreceptoras/enzimologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6 , Humanos , Dados de Sequência Molecular , Homologia de Sequência do Ácido NucleicoRESUMO
cDNA clones encoding the beta-subunit of the photoreceptor cGMP phosphodiesterase-(PDE) were isolated from a human retinal library. The encoded polypeptide has 854 amino acid residues with calculated molecular mass of 98416 Da. Alignment of the deduced amino acid sequence with the previously analysed alpha-, beta- and alpha'-subunits of the bovine and mouse PDEs demonstrates highly significant similarities. We have also isolated, from a genomic library, two overlapping recombinant lambda phage clones containing 26 kb of the human PDE beta-subunit gene. The cloning of the human gene and the knowledge of its genomic organization will allow the rapid assessment of the role of this gene in the causation of human retinopathies.
