MOLECULAR-CLONING, FUNCTIONAL EXPRESSION, AND SELECTIVE REGULATION OFOVINE PROSTAGLANDIN-H SYNTHASE-2

Structural characterization for ovine prostaglandin H synthase-1 (PGHS -1) is extensive, but the corresponding structure for the homologous o vine PGHS-2 isoform is undefined. Accordingly, we isolated a full-leng th (3.4 kb) ovine PGHS-2 cDNA from a primary-culture cell model (ovine tracheal epithelial cells) originally described as containing both PG HS isoforms. Analysis of ovine PGHS-2 cDNA sequence indicated conserva tion of critical amino acid residues, but differences in other hydroph ilic regions allowed for the development of an anti-peptide antibody h ighly selective for PGHS-2. Enzymatic activities of the recombinant ov ine PGHS isozymes indicated significant differences in response to asp irin-acetylation consistent with the characteristics of endogenous cel lular PGHS activities under basal and serum-induced conditions. The re sults fully account for previous evidence of two distinct PGHS activit ies in cultured airway epithelial cells and provide for additional def inition of PGHS structure-function relationships. (C) 1996 Academic Pr ess.