REGULATED ASSEMBLY OF TENDON EXTRACELLULAR MATRIX

描述(由申请人提供)：本申请的重点是 确定肌腱细胞外基质组装的机制 初始纤维组装的独立调节以及在 长度和直径。肌腱特异性基质的组装是一个多步骤的过程 进程。我们的模型是胶原蛋白纤维最初是以离散的形式组装的 在显影过程中并入纤维中的原纤维中间体 矩阵。这之后是纤维的受控生长和成熟 这些预制中间体。这涉及组装以形成更长的(线性 生长)和更大直径(侧向生长)的纤维。对这一问题的解释 调节这些步骤的机制对于理解正常 肌腱发育。本申请的具体目的是：(1)定义 与纤维形成相关的纤维亚群，并分析 肌腱发育过程中原纤维长度的变化，(2)表征其作用 异型I/III型胶原相互作用在组装调控中的作用 肌腱原纤维的中间产物；(3)阐明核心蛋白、鲁米肯和 纤维调素在肌腱纤维形成特定步骤调控中的作用； (4)探讨XIV型胶原在纤维生长调节中的作用。我们 将利用缺乏III型胶原、XIV型胶原的转基因小鼠， 具有结构的、形态计量的、分子的、 生化和免疫化学方法。一种假设是， 胶原纤维的异型相互作用是其调控的主要机制 胶原蛋白最初组装成原纤维的中间产物。此外, 富含亮氨酸的重复蛋白在肌腱发育的不同阶段发挥作用 调节纤维形成的具体步骤。不同的表达模式， 结合部位和结合亲和力调节这些效应。我们还假设 这种XIV型胶原参与调节转化为和 通过线性增长控制进展。这些研究将定义 肌腱特异性基质组装过程中调控步骤的机制 发展，并导致潜在的操纵在生长，伤害和 修复，以及对遗传性疾病的理解。

DESCRIPTION (provided by applicant): The focus of this application is to determine the mechanisms of tendon extracellular matrix assembly that allow for the independent regulation of initial fibril assembly as well as growth in length and diameter. Assembly of the tendon-specific matrix is a multistep process. Our model is that collagen fibrils are initially assembled as discrete fibril intermediates that are incorporated into fibers within the developing matrix. This is followed by a regulated growth and maturation of fibrils from these preformed intermediates. This involves assembly to form longer (linear growth) and larger diameter (lateral growth) fibrils. The elucidation of the mechanisms regulating these steps is essential to an understanding of normal tendon development. The Specific Aims of this application are to: (1) define the fibril sub-populations associated with fibrillogenesis and analyze the changes in fibril length during tendon development, (2) characterize the roles of heterotypic type I/III collagen interactions in the regulation of assembly of tendon fibril intermediates; (3) elucidate the roles of decorin, lumican and fibromodulin in the regulation of specific steps in tendon fibrillogenesis; and (4) determine the roles of type XIV collagen in regulation of fibril growth. We will utilize transgenic mice deficient in type III collagen, type XIV collagen, decorin, fibromodulin or lumican with structural, morphometric, molecular, biochemical and immunochemical approaches. One hypothesis is that the heterotypic interaction of fibrillar collagens is a major mechanism regulating the initial assembly of collagen into fibril intermediates. In addition, leucine-rich repeat proteins act at different stages in tendon development to regulate specific steps in fibrillogenesis. Different expression patterns, binding sites and binding affinities mediate these effects. We also hypothesize that type XIV collagen is involved in regulating the transition into and controlled progression through linear growth. These studies will define the mechanisms regulating the steps in tendon-specific matrix assembly during development and lead to potential manipulations during growth, injury and repair, as well as to the understanding of inherited disorders.