The 3'-untranslated region of rat lysyl oxidase cDNA

The cloning of the 3'-untranslated region of rat lysyl oxidase cDNA was completed. cDNA clones were generated by reverse transcriptase PCR from neonatal rat aorta smooth muscle cell RNA, and sequenced. Several polyadenylated clones were obtained, providing 2.1 kb of new sequence. Clones were polyadenylated at three different positions. The cDNA clones were verified by PCR-cloning and sequencing of genomic DNA, and by Northern blotting studies. Evidence is presented that the polyadenylation patterns of rat lysyl oxidase mRNAs are similar, but not identical to mouse or human transcripts. Interestingly, the nonconsensus polyadenylations in rat did not occur at the same positions as was found in mouse lysyl oxidase cDNAs. Multiple transcription initiation sites were found by primer extension mapping. Thus, the complex pattern of rat lysyl oxidase mRNAs on Northern blots is principally due to differential use of polyadenylation signals, and to the occurrence of multiple transcription initiation sites. All clones lacked a previously reported 258 bp segment nearly identical to a conserved segment of the 3'-untranslated region of elastin cDNA. We conclude that the elastin-like sequence previously reported in rat lysyl oxidase cDNA is not a species-specific sequence, and most probably resulted from spurious ligation reactions during construction of the cDNA library.