The calmodulin-dependent phosphodiesterase gene PDE1C encodes several functionally different splice variants in a tissue-specific manner.
We report here the identification of cDNAs for three new mouse PDE1C splice variants and the characterization of their kinetics, regulation by Ca2+, sensitivities to inhibitors, and tissue/cellular expression patterns. Sequence analysis indicated that these three cDNAs (PDE1C1, PDE1C4, and PDE1C5), together with our previously reported PDE1C2 and PDE1C3, are alternative splice products of the PDE1C gene. The results from RNase protection analysis and in situ hybridization indicated that the expression of the different PDE1C splice variants is differentially regulated in a tissue/cell-specific manner. Particularly, high levels of PDE1C mRNAs were found in the olfactory epithelium, testis, and several regions of mouse brain such as cerebellar granule cells. All of these splice variants have similar kinetic properties, showing high affinities and approximately the same relative Vmax values for both cAMP and cGMP. However, they responded to Ca2+ stimulation differently. In addition, they show different sensitivities to the calmodulin-dependent phosphodiesterase inhibitors, KS505a and SCH51866. Substrate competition experiments suggested the presence of only one catalytic site on these PDE1C isozymes for both cAMP and cGMP. In summary, these findings suggest that the PDE1C gene undergoes tissue-specific alternative splicing that generates structurally and functionally diverse gene products.
Yan
C
C
Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA.
Zhao
A Z
AZ
Bentley
J K
JK
Beavo
J A
JA
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology*; D019556:COS Cells; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D002531:Cerebellum / Q000201:enzymology; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; D017931:DNA Primers; D014644:Genetic Variation; D007527:Isoenzymes / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D009474:Neurons / Q000201:enzymology; D009928:Organ Specificity; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D014162:Transfection
D017931:DNA Primers; D007527:Isoenzymes; D010726:Phosphodiesterase Inhibitors; D012333:RNA, Messenger; D011994:Recombinant Proteins; D010727:Phosphoric Diester Hydrolases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054677:Cyclic Nucleotide Phosphodiesterases, Type 1; C517273:Pde1C protein, mouse; C517274:Pde1C protein, rat; D002118:Calcium