Cloning Two Isoforms of Rat Cyclooxygenase: Differential Regulation of Their Expression

L. Feng, W. Q. Sun, Y. Y. Xia, W. W. Tang, P. Chanmugam, E. Soyoola, C. B. Wilson, D. Hwang

Research output: Contribution to journalArticle

445 Scopus citations

Abstract

Two isoforms of cyclooxygenase (COX) have been identified in eukaryotic cells: COX-1 encoded by a 2.8-kb mRNA, and a mitogen-inducible COX-2 encoded by a 4-kb mRNA. We have cloned the COX-1 and COX-2 cDNAs from the cDNA library constructed from lipopolysaccharide (LPS)-stimulated rat peritoneal macrophages. The deduced amino acid sequence showed that COX- I contained 602 amino acids, whereas COX-2 contained 604 amino acids. There is 95% conservation of the nucleotide sequence in the open reading frame of COX-1 between the rat and the mouse, while the homology of the 3′ untranslated region is 68% except for a 150 bp segment adjacent to the stop codon which is nonhomologous with the mouse. Transfection of both COX cDNAs into Cos-7 cells resulted in increased COX activity. In rat vascular smooth muscle cells, interleukin-1β selectively increased the expression of COX-2, but not that of COX-1, as assessed by enzyme activity, immunoprecipitation of COX proteins, and mRNA analysis. Only the brain among tissues tested exhibits basal expression of COX-2 as the major form of the enzyme. However, COX-2 mRNA was expressed in vivo in the lung and kidney, but not in the heart, after systemic administration of LPS, suggesting that COX-2 but not COX-1 plays a major role in producing COX-derived products of arachidonic acid during endotoxic shock. Thus, the two COX isoforms were differentially expressed, and COX-2 was selectively induced in response to inflammatory stimuli in rats.

Original languageEnglish (US)
Pages (from-to)361-368
Number of pages8
JournalArchives of Biochemistry and Biophysics
Volume307
Issue number2
DOIs
StatePublished - Dec 1993
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Biophysics
  • Biochemistry

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    Feng, L., Sun, W. Q., Xia, Y. Y., Tang, W. W., Chanmugam, P., Soyoola, E., Wilson, C. B., & Hwang, D. (1993). Cloning Two Isoforms of Rat Cyclooxygenase: Differential Regulation of Their Expression. Archives of Biochemistry and Biophysics, 307(2), 361-368. https://doi.org/10.1006/abbi.1993.1601