CHARACTERIZATION OF HUMAN MATRILIN-3 (MATN3)

We have isolated a cDNA clone for human matrilin-3 from a cartilage-sp ecific cDNA library. The polypeptide predicted from the nucleotide seq uence of this clone shared 83% identity with matrilin-3 from mouse and 61% with that from chicken. It was composed of 486 amino acid residue s that were arranged in seven domains: a signal peptide, a von Willebr and factor A domain, four EGF repeats, and an Lu-helical region. The g ene for human matrilin-3 (MATN3) was assigned to chromosome region 2p2 4-p23. The corresponding mRNA of 2.8 kb was expressed in every type of cartilage investigated thus far. It was also produced in vitro by pri mary chondrocytes isolated from articular cartilage. However, dediffer entiated chondrocytes of the third passage did not express it at all. Matrilin-3 might therefore serve as a marker for the differentiation s tate of chondrocytes. (C) 1998 Academic Press.