Presence of 3′UTR AU-rich elements in prostaglandin pathway transcripts. The representation of the human mRNAs is not to scale. The filled triangles represent AU-rich sequences, AUUUA, contained within the 3′UTR; triangles adjacent to one another indicate multiple repeat elements. Identification of AU-rich elements was accomplished with AREsite (rna.tbi.univie.ac.at/cgi-bin/AREsite.cgi) [143] using the representative transcript containing the greatest number of AUUUA motifs although polyadenylation and splice variants can yield shortened 3′UTRs as observed with COX-1, COX-2, and EP3 mRNAs