Kimura T, Mattei M G, Stevens J W, Goldring M B, Ninomiya Y, Olsen B R
Department of Anatomy and Cellular Biology, Harvard Medical School, Boston, Massachusetts 02115.
Eur J Biochem. 1989 Jan 15;179(1):71-8. doi: 10.1111/j.1432-1033.1989.tb14522.x.
Type IX collagen is found in hyaline cartilage, where it is associated with type II collagen in quarter-staggered collagen fibrils. Chicken type IX collagen has been extensively characterized and shown to contain molecules with three triple-helical domains, interspersed with non-triple-helical sequences. The molecule contains three, genetically distinct, subunits and one of these subunits carries a covalently bound glycosaminoglycan side chain. In the present report, we describe for the first time the primary structure of mammalian type IX collagen chains, based on cloning and sequencing of cDNA from rat and human cDNA libraries. The results suggest that mammalian alpha 1(IX) chains have the same multi-domain structure as the avian protein. We also demonstrate, by in situ hybridization of chromosome spreads, that the human alpha 1(IX) collagen gene is located on the long arm of chromosome 6. The cloning of human type IX collagen cDNA provides a probe for molecular studies of human chondrodysplasias that may involve abnormalities in this extracellular collagen-proteoglycan.
IX型胶原蛋白存在于透明软骨中，在那里它与II型胶原蛋白一起存在于四分之一交错排列的胶原纤维中。鸡IX型胶原蛋白已被广泛表征，并显示含有具有三个三螺旋结构域的分子，这些结构域穿插着非三螺旋序列。该分子包含三个基因不同的亚基，其中一个亚基带有共价结合的糖胺聚糖侧链。在本报告中，我们首次基于从大鼠和人类cDNA文库中克隆和测序cDNA，描述了哺乳动物IX型胶原链的一级结构。结果表明，哺乳动物α1(IX)链具有与禽类蛋白质相同的多结构域结构。我们还通过染色体铺展的原位杂交证明，人类α1(IX)胶原基因位于6号染色体的长臂上。人类IX型胶原蛋白cDNA的克隆为可能涉及这种细胞外胶原蛋白聚糖异常的人类软骨发育不全的分子研究提供了探针。
