Cloning of rat aorta lysyl oxidase cDNA: complete codons and predicted amino acid sequence

Abstract

Lysyl oxidase cDNA clones were identified by their reactivity with anti-bovine lysyl oxidase in a neonatal rat aorta cDNA .lambda.gt11 expression library. A 500-bp cDNA sequence encoding four of six peptides derived from proteolytic digests of bovine aorta lysyl oxidase was found from the overlapping cDNA sequences of two positive clones. The library was rescreened with a radiolabeled cDNA probe made from one of these clones, thus identifying an additional 13 positive clones. Sequencing of the largest two of these overlapping clones resulted in 2672 bp of cDNA sequence containing partial 5''- and 3''-untranslated sequences of 286 and 1159 nucleotides, respectively, and a complete open reading frame of 1227 bp encoding a polypeptide of 409 amino acids (46 kDa), consistent with the 48 .+-. 3 kDa cell-free translation product of rat smooth muscle cell RNA that was immunoprecipitated by anti-bovine lysyl oxidase. The rat aorta cDNA-derived amino acid sequence contains the sequence of each of the six peptides isolated and sequenced from the 32-kDa bovine aorta enzyme, including the C-terminal peptide with sequence identity of 96%. Northern blots screened with lysyl oxidase cDNA probes identified hybridizing species of 5.8 and 4.5 kb in mRNA of rat aorta and lung, while dot blot analyses were negative for lysyl oxidase mRNA in preparations of rat brain, liver, kidney, and heart. A 258-bp segment of the 3''-untranslated region of lysyl oxidase cDNA is 93% identical with a highly conserved region of the 3''-untranslated sequence of rat elastin cDNA. Southern blotting of rat genomic DNA with lysyl oxidase cDNA probes indicated that the lysyl oxidase gene is located at a single locus and does not appear to be a member of a multigene family. A potential stem-loop structure was found in the 3''-untranslated region of the cDNA. The deduced amino acid sequence contains a putative signal peptide, in addition to sequences that are similar to those of other known copper proteins.