title: Calmodulin-dependent cyclic nucleotide phosphodiesterase (PDE1) splice variants from bovine cardiac muscle.
abstract: Calmodulin-dependent cyclic nucleotide phopshodiesterase (PDE1) has been extensively characterized and is a key enzyme involved in the complex interaction between cyclic nucleotide and Ca(2+) second-messenger systems. It is well established that PDE1 exists in different isozymes. For example, bovine brain tissue has two PDE1 isozymes (PDE1A2 and PDE1B1) whereas only one form (PDE1A1) is reported in bovine cardiac tissue. In this study, we report the cloning of two cDNA splice variants of PDE1: PDE1-small and PDE1-large, from bovine cardiac tissue. Their amino acid sequence similarity to PDE1 sequences from other mammalian species showed that all are very conserved, suggesting their importance in cellular functions. Interestingly, compared to other mammalian species, bovine PDE1A, PDE-small and PDE-large show a deletion at the C-terminal end of the catalytic domain of the gene. Although the significance of this deletion at this crucial location of the gene is not known, we have successfully over-expressed both PDE1-small and PDE1-large splice variants in E. coli and these splice variants are characterized in terms of Western blot, biotinylated calmodulin overlay and peptide mass fingerprinting. Results from these studies suggested that these two splice variants belong to the PDE1 superfamily. To our knowledge, this is the first report on cloning and characterization of these cDNA variants from bovine cardiac tissue. Since there are at least two isoforms of PDE1 in bovine heart tissue, this merits further in-depth study.
authors.affiliation: Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E5.
authors.forename: Shankar B
authors.initials: SB
authors.lastname: Das
authors.forename: Chris
authors.initials: C
authors.lastname: Dinh
authors.forename: Sachin
authors.initials: S
authors.lastname: Shah
authors.forename: Doug
authors.initials: D
authors.lastname: Olson
authors.forename: Andrew
authors.initials: A
authors.lastname: Ross
authors.forename: Ponniah
authors.initials: P
authors.lastname: Selvakumar
authors.forename: Rajendra K
authors.initials: RK
authors.lastname: Sharma
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D004926:Escherichia coli / Q000378:metabolism; D017353:Gene Deletion; D006801:Humans; D007527:Isoenzymes; D008969:Molecular Sequence Data; D009206:Myocardium / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000502:physiology*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
chemical_list: D007527:Isoenzymes; D010727:Phosphoric Diester Hydrolases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; C517265:PDE1A protein, human; C517266:PDE1B protein, human