OSTEOGENIC FACTOR FROM DENTIN MATRIX

牙本质细胞外基质含有一种蛋白质因子，该因子具有 调节培养的成纤维细胞表型表达的能力， 并将它们转化为软骨细胞特征的产品。 的 牙本质基质具有类似 BMP 的活性。 也就是说，牙本质基质种植体 体内植入肌肉，在植入物模型上诱导骨形成 一种完全类似于具有 BMP 能力的骨基质的方式。 在 之前的项目期间，牙本质体外软骨形成因子（CIA）是 纯化并部分表征。 中央情报局的组成截然不同 来自骨 BMP 和 TGF-β 超家族的其他成员。 的 CIA 作为 Mr 6000 单体活跃，未受到减少的影响，并且 不包含 TGF-β 共有的 C 端富含 Cys 的区域 超家族。 N 端测序已导致制备 核苷酸探针和假定的 CIA 克隆的检测 已测序。 原位杂交研究已启动以定位 中央情报局的mRNA。 延续期的具体目标是： 1）从序列和基因结构方面全面表征CIA； 2） 生产可行数量的重组 CIA 并使用该蛋白质 体外检查 CIA 作用机制；以及 3) 确定体内 CIA 载体植入物的体内活性。 在目标 2 中， 胶原蛋白和蛋白多糖产生的表型变化 细胞表面受体的性质和数量，以及细胞的诱导 将在大鼠肌肉成纤维细胞和 定义的非成骨系，C3H10T1/2。 cDNA差异文库将是 准备并筛选。 一个重要的新发展是 在培养物中诱导致密的软骨样结节。 这些结节可以 被植入体内并将作为替代方案进行研究 骨/软骨感应修复系统。 除了它们固有的 兴趣，这 3 条调查线应该会带来更好的结果 了解正常情况下细胞分化的调节 发育以及硬组织的修复。

The dentin extracellular matrix contains a protein factor which has the ability to modulate the phenotypic expression of cultured fibroblasts, and switch them to produce products characteristic of chondrocytes. The dentin matrix has a BMP-like activity. That is, a dentin matrix implant into muscle in vivo induces bone formation on the model of the implant in a fashion entirely analogous to BMP-competent bone matrix. In the previous project period the dentin in vitro chondrogenic factor (CIA) was purified and partially characterized. The CIA composition was distinct from that of bone BMP and other members of the TGF-beta superfamily. The CIA was active as a Mr 6000 monomer, was unaffected by reduction, and did not contain the C-terminal Cys-rich region common to the TGF-beta superfamily. N-Terminal sequencing has led to the preparation of nucleotide probes and detection of putative CIA-clones which have been sequenced. In situ hybridization studies have been initiated to localize the CIA mRNA. The specific objectives of the continuation period are to: 1) fully characterize the CIA in terms of sequence and gene structure; 2) produce workable quantities of recombinant CIA and use the protein to examine in vitro the mechanism of CIA action;, and, 3) determine the in vivo activity of CIA+ carrier implants. In Objective 2, the nature of the phenotypic changes in collagen and proteoglycan production, the nature and number of cell surface receptors, and the induction of cell regulatory proteins will be studied in rat muscle fibroblasts and in the defined nonosteogenic line, C3Hl0T1/2. cDNA difference libraries will be prepared and screened. An important new development has been the induction of dense cartilage-like nodules in culture. These nodules can be implanted in vivo and will be investigated as an alternate bone/cartilage inductive repair system. Aside from their intrinsic interest, these 3 lines of investigation should lead to a better understanding of the regulation of cell differentiation during normal development as well as to the repair of hard-tissues.