Exposito J Y, D'Alessio M, Di Liberto M, Ramirez F
Brookdale Center for Molecular Biology, Mt. Sinai School of Medicine, New York, New York 10029.
J Biol Chem. 1993 Mar 5;268(7):5249-54.
We isolated several overlapping cDNAs from Strongylocentrotus purpuratus coding for a nonfibrillar collagen chain structurally homologous to the vertebrate type IV collagen chains and arbitrarily termed 3 alpha chain. The deduced amino acid sequence of the sea urchin polypeptide includes a 28-residue signal peptide, a 14-residue amino-terminal non-collagenous segment, a triple-helical domain of 1390 residues containing 23 imperfections, and a 226-residue carboxyl-terminal non-collagenous region. Comparison of the sea urchin amino- and carboxyl-terminal non-collagenous domains with those of the vertebrate type IV collagen chains indicated a high level of sequence identity to the alpha 1 (IV) and alpha 5 (IV) chains. This evolutionary relationship was further strengthened by the analysis of the genomic organization of the 5' portion of the sea urchin gene, which also provided the composition of some of the upstream sequences. In addition, this work demonstrated that our gene product is identical to that encoded by the partial cDNA clone recently isolated by others (Wessel, G. M., Etkin, M., and Benson, S. (1991) Dev. Biol. 148, 261-272) who demonstrated its involvement in the biomineralization process of cultured mesenchyme cells.
我们从紫球海胆中分离出了几个重叠的cDNA，它们编码一种非纤维状胶原链，该胶原链在结构上与脊椎动物IV型胶原链同源，并被随意命名为3α链。海胆多肽的推导氨基酸序列包括一个28个残基的信号肽、一个14个残基的氨基末端非胶原片段、一个由1390个残基组成的三螺旋结构域，其中有23个不完美之处，以及一个226个残基的羧基末端非胶原区域。将海胆的氨基末端和羧基末端非胶原结构域与脊椎动物IV型胶原链的相应结构域进行比较，结果表明与α1(IV)和α5(IV)链具有高度的序列同一性。通过对海胆基因5′部分基因组组织的分析，进一步加强了这种进化关系，该分析还提供了一些上游序列的组成。此外，这项工作表明，我们的基因产物与最近其他人分离的部分cDNA克隆所编码的产物相同（Wessel，G.M.，Etkin，M.，和Benson，S.（1991）《发育生物学》148，261 - 272），他们证明了其参与培养间充质细胞的生物矿化过程。
