Cyclooxygenase expression in canine platelets and Madin-Darby canine kidney cells.
OBJECTIVE
To examine cyclooxygenase (COX) expression in canine platelets and Madin-Darby canine kidney (MDCK) cells in culture.


METHODS
Canine platelets and MDCK cells.


METHODS
Total RNA was recovered from isolated canine platelets and MDCK cells. Northern blot analysis and reverse transcription-polymerase chain reaction (RT-PCR), using complementary DNA probes and primers designed from the human COX sequences, were used to determine COX-1 and -2 (cyclooxygenase isoforms 1 and 2) messenger RNA (mRNA) expression.


RESULTS
Following northern blot analysis, canine platelets were found to express only the 2.8-kb COX-1 transcript; COX-2 was not detected. Canine MDCK cells expressed the 4.5-kb COX-2 transcript, in addition to the 2.8-kb COX-1 transcript. A single DNA band of 270 base pairs was identified following gel electrophoresis of the product obtained from RT-PCR of mRNA from canine platelets. Sequencing revealed that this PCR product was 90% homologous to a portion of the human COX-1 gene (Genbank M59979).


CONCLUSIONS
Detection of COX-1 by RT-PCR of RNA obtained from canine platelets is a novel finding. The 90% homology of the PCR product with the human sequence suggests strong conservation between the canine and human COX-1 gene. Cloning and sequencing of the canine gene will be required to fully characterize homologous regions. Because of the importance of COX in the inflammatory process and as a potential target of currently available nonsteroidal anti-inflammatory drugs (NSAID), a better understanding of canine COX may improve our ability to use NSAID appropriately, achieve efficacy, and avoid potential adverse drug effects in dogs.
Kay-Mugford
P A
PA
Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Canada.
Benn
S J
SJ
LaMarre
J
J
Conlon
P D
PD
D000818:Animals; D001483:Base Sequence; D001792:Blood Platelets / Q000201:enzymology*; D002460:Cell Line; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D004285:Dogs; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000097:blood / Q000235:genetics*; D007668:Kidney / Q000201:enzymology; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D011451:Prostaglandin-Endoperoxide Synthases / Q000097:blood / Q000235:genetics*; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014158:Transcription, Genetic
D007527:Isoenzymes; D008565:Membrane Proteins; D012333:RNA, Messenger; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; C496512:Ptgs1 protein, mouse