The major structural elements of most tissues are formed from type I, II and III collagens, which are made as procollagens. An aminopropeptidase called ADAMTS2 can remove the N-propeptide of all three procollagens, but,surprisingly, ADAMTS2 defects in animals cause only dermatosparaxis (severe skin fragility caused by a lack of collagen), suggesting that its homologues,ADAMTS3 and ADAMTS14, compensate for its loss in tissues other than skin. Now,by studying the temporal and spatial expression of these proteases and their procollagen substrates during mouse embryogenesis, Le Goff and co-workers show that these closely related proteins have distinct biological roles because of different tissue-specific expression patterns (see p. ). For example,the expression pattern of Adamts3 identifies it as the major procollagen I and II aminopropeptidase during development, and studies of Adamts2-null mice reveal that ADAMTS2 is the predominant procollagen III-processing enzyme in mice. Other results confirm that dermatosparaxis occurs in Adamts2-null mice because neither ADAMTS3 nor ADAMTS14 is significantly expressed in adult mouse skin.
