Cloning and characterization of mammalian homologs of the Drosophila dunce+ gene.

Abstract

A probe representing the Drosophila dunce'(dnc') gene, the structural gene for a cAMP phosphodiesterase (PDEase), detects homologous sequences in many different organisms, including mouse, rat, and human. Genomic and cDNA clones representing a homolog of the Drosophila dnc' gene were isolated from rat libraries and characterized. This gene has been named ratdnc-1. One cDNA clone defines a large open reading frame of 41.8 kilobases (kb), predicting a protein sequence of 610 amino acids with significant homology to a conserved domain of -275 residues found in most otherPDEases. The amino acid identity value to the Drosophila cAMP PDEase within this domain is a striking 75%. Other cDNA clones show blocks of sequence divergence from this cDNA clone close to the predicted N terminus, indicating the potential existence of a family of related enzymes encoded by alternatively spliced messenger RNAs from ratdnc-1. Genomic blotting experiments suggest the existence of at least one other rat gene with homology to ratdnc-1. RNAs homologous to ratdnc-1 are heterogeneous in size between tissues, with heart containing a major transcript of 4.4 kb and brain one of4.0 kb.The potential identity of the product of the ratdnc-1 gene with known PDEases is discussed.

Identification of cyclic AMP‐phosphodiesterase variants from the PDE4D gene expressed in human peripheral mononuclear cells

“…Four PDE4 genes (PDE4A, PDE4B, PDE4C, PDE4D) are expressed in rat [16][17][18][19], mouse [20], and human [21][22][23][24][25], and their characterization has shown a close relationship between genes from two different species [14]. Furthermore, for three out of four rat and human genes, multiple mRNA variants and corresponding protein products have been detected [13,14].…”

Cloning and expression of cDNA for a human low-Km, rolipram-sensitive cyclic AMP phosphodiesterase.

“…A 32p_ labeled 883-base-pair (bp) PstI fragment, containing the conserved region of a rat brain cDNA clone (RD1) coding for a low-Km cAMP PDEase (13), was prepared by nick translation (26) and used to screen a granulocyte-macrophage colony-stimulating factor-stimulated human monocyte library constructed in XZAP (Stratagene Inc., La Jolla, Calif.). A total of 12 clones were isolated and partially characterized by restriction mapping.…”

“…and testis low-Km cAMP-specific PDEases (10,13,17,32). With the exception of one of the yeast and the slime mold PDEases, significant amino acid sequence homology exists among these enzyme species (3,10,13,17).…”

“…With the exception of one of the yeast and the slime mold PDEases, significant amino acid sequence homology exists among these enzyme species (3,10,13,17). In fact, several of the rat PDEase cDNAs were cloned by virtue of their DNA sequence homology to the Drosophila dnc+ gene (13,32), a gene required for normal memory of learned information in flies (15). The isolation of four distinct rat cAMP PDEase cDNA clones (from brain and testis) suggests the existence of a multigene family (10,13,32).…”

“…In fact, several of the rat PDEase cDNAs were cloned by virtue of their DNA sequence homology to the Drosophila dnc+ gene (13,32), a gene required for normal memory of learned information in flies (15). The isolation of four distinct rat cAMP PDEase cDNA clones (from brain and testis) suggests the existence of a multigene family (10,13,32). The possibility that the low-Km cAMP PDEases play an essential role in central nervous system function has been suggested by biochemical studies showing that some of the enzymes are selectively inhibited by compounds which exhibit antidepressant properties, such as RO 20-1724 and rolipram (3,18,38).…”