THE 3'-UNTRANSLATED REGION OF RAT LYSYL OXIDASE CDNA

The cloning of the 3'-untranslated region of rat lysyl oxidase cDNA wa s completed. cDNA clones were generated by reverse transcriptase PCR f rom neonatal rat aorta smooth muscle cell RNA, and sequenced. Several polyadenylated clones were obtained, providing 2.1 kt, of new sequence . Clones were polyadenylated at three different positions. The cDNA cl ones were verified by PCR-cloning and sequencing of genomic DNA, and b y Northern blotting studies. Evidence is presented that the polyadenyl ation patterns of rat lysyl oxidase mRNAs are similar, but not identic al to mouse or human transcripts. Interestingly, the nonconsensus poly adenylations in rat did not occur at the same positions as was found i n mouse lysyl oxidase cDNAs. Multiple transcription initiation sites w ere found by primer extension mapping. Thus, the complex pattern of ra t lysyl oxidase mRNAs on Northern blots is principally due to differen tial use of polyadenylation signals, and to the occurrence of multiple transcription initiation sites. All clones lacked a previously report ed 258 bp segment nearly identical to a conserved segment of the 3'-un translated region of elastin cDNA. We conclude that the elastin-like s equence 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.