Expression Pattern and Gene Characterization ofAsporin

• Published in: The Journal of biological chemistry 2001-04, Vol.276 (15), p.12212-12221
• Main Authors: Henry, Stephen P., Takanosu, Masamine, Boyd, Tanya C., Mayne, Pauline M., Eberspaecher, Heidi, Zhou, Wei, de Crombrugghe, Benoit, Höök, Magnus, Mayne, Richard
• Format: Article
• Language: English
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M011290200

We have discovered a new member of the class I small leucine-rich repeat proteoglycan (SLRP) family which is distinct from the other class I SLRPs since it possesses a unique stretch of aspartate residues at its N terminus. For this reason, we called the molecule asporin. The deduced amino acid sequence is about 50% identical (and 70% similar) to decorin and biglycan. However, asporin does not contain a serine/glycine dipeptide sequence required for the assembly of O-linked glycosaminoglycans and is probably not a proteoglycan. The tissue expression ofasporin partially overlaps with the expression ofdecorin and biglycan. During mouse embryonic development, asporin mRNA expression was detected primarily in the skeleton and other specialized connective tissues; very little asporin message was detected in the major parenchymal organs. The mouse asporin gene structure is similar to that of biglycan and decorin with 8 exons. The asporin gene is localized to human chromosome 9q22–9q21.3 where asporin is part of a SLRP gene cluster that includes extracellular matrix protein 2,osteoadherin, and osteoglycin. Further analysis shows that, with the exception of biglycan, all known SLRP genes reside in three gene clusters.