THE ROLE OR TYPE XXVII COLLAGEN IN SKELETOGENESIS

描述(由申请人提供)： COL27A1是一个新发现的基因，它编码XXVI型胶原的前-阿尔法链。它是形成纤维的胶原蛋白的一种，每一种胶原蛋白都与骨骼、皮肤或心血管系统的一种疾病有关。COL27A1在进化过程中是保守的，在人类胶原蛋白中，与无脊椎动物的纤维胶原基因最相似，提示了一种重要的生物学功能。初步数据表明，COL27A1主要在软骨中表达，包括骨胶原，在眼和视囊中也有表达。这种表达模式让人想起II型和XI型胶原基因，当它们突变时，会导致软骨发育不良。因此，我们假设XXVII型胶原和其他纤维状胶原蛋白一样，是这些组织细胞外基质(ECM)的重要组成部分，从而使COL27A1成为软骨形成以及骨、眼和耳部发育异常的疾病的极佳候选基因。为了开始检验这一假设，将实现三个具体目标。首先，XXVI型胶原将从培养的大鼠软骨肉瘤细胞中分离出来，并根据其翻译后修饰及其三聚体分子的性质进行生化特征表征。其次，COL27A1的发育特异性组织表达谱将通过RT-PCR、原位杂交和免疫组织化学来确定。第三，XXVI型胶原相对于细胞外基质其他成员的位置将通过免疫金电子显微镜和交联蛋白的质谱分析来确定。这些研究对于推动这一领域的发展是必要的，并将为软骨、骨骼、光学和耳部组织的发展提供新的见解。他们还将为未来研究XXVI型胶原的确切生物学作用及其与结缔组织疾病(如脊柱骨骺和干骺端软骨发育不良)发病机制的联系铺平道路。

DESCRIPTION (provided by applicant): COL27A1 is a newly discovered gene that encodes a pro-alpha chain of type XXVII collagen. It is a member of the fibril-forming class of collagens, of which each member is linked to a disease of the skeletal, integumentary, or cardiovascular systems. COL27A1 is conserved through evolution and among human collagens, most closely resembles invertebrate fibrillar collagen genes, suggestive of an important biological function. Preliminary data indicate that COL27A1 is expressed primarily in cartilage, including the anlagen of bone, and in the eye and optic capsule. This pattern of expression is reminiscent of the type II and XI collagen genes, which when mutated result in forms of chondrodysplasia. Thus, we hypothesize that type XXVII collagen, like the other fibrillar collagens, is an essential component of the extracellular matrices (ECM) of these tissues, thereby making COL27A1 an excellent candidate locus for disorders in which abnormalities in chondrogenesis, and bone, ocular and otic development occur. To begin testing this hypothesis three specific aims will be accomplished. First, type XXVII collagen will be isolated from cultured rat chondrosarcoma cells and biochemically characterized in terms of its post-translational modifications and the nature of its trimeric molecule. Second, a developmentally specific tissue expression profile of COL27A1 will be determined by RT-PCR, in situ hybridization, and immunohistochemistry. Third, the location of type XXVII collagen in relation to other members of the extracellular matrix will be determined by immuno-gold electron microscopy, and by mass spectrometric analysis of cross-linked proteins. These studies are necessary to advance the field and will provide novel insights into the development of cartilaginous, skeletal, optic, and otic tissues. They will also pave the way for future investigations into the exact biological role of type XXVII collagen and its link to the pathogenesis of connective tissue diseases such as the spondyloepiphyseal and metaphyseal chondrodysplasias.