The LOXL2 gene encodes a new lysyl oxidase-like protein and is expressed at high levels in reproductive tissues

We have reported in this paper the complete cDNA sequence, gene structure, and tissue-specific expression of LOXL2, a new amine oxidase and a member o f an emerging family of human lysyl oxidases, The predicted amino acid sequ ence, from several overlapping cDNA clones isolated from placenta and splee n cDNA libraries, shared extensive sequence homology with the conserved cop per-binding and catalytic domains of both lysyl oxidase (LOX) and the lysyl oxidase-like (LOXL) protein. These conserved domains are encoded by five c onsecutive exons within the LOX, LOXL, and LOXL2 genes that also maintained exon-intron structure conservation. In contrast, six exons encoding the am inoterminal domains diverged both in sequence and structure. Exon 1 of the LOXL2 gene does not encode a signal sequence that is present in LOX and LOX L, suggesting a different processing and intracellular localization for thi s new protein. Expression of the LOXL2 gene was detected in almost all tiss ues with the highest steady state mRNA levels in the reproductive tissues, placenta, uterus and prostate. In situ hybridization identified placental s yncytial and cytotrophoblasts responsible for the synthesis of LOXL2 mRNA a nd demonstrated a spatial and temporal expression pattern unique to the LOX L2 gene.