Weiss R E, Reddi A H
Proc Natl Acad Sci U S A. 1980 Apr;77(4):2074-8. doi: 10.1073/pnas.77.4.2074.
The biosynthesis of fibronectin during the in vivo development of matrix-induced endochondral bone was investigated by using [35S]methionine in rats. The dmineralized bone matrix that was implanted subcutaneously to induce local bone formation bound circulating fibronectin. This may be an important initial requirement for cell attachment to the matrix. Fibronectin was present throughout the development of bone but accounted for the largest percentage of total protein synthesized during mesenchymal cell proliferation and hematopoiesis. Fibronectin was identified in tissue extracts by its (i) comigration on electrophoretic NaDodSO4/polyacrylamide gels with human and rat plasma fibronectin, (ii) affinity for denatured collagen, (iii) crossreactivity with purified antibody of rat plasma fibronectin, and (iv) insensitivity to collagenase digestion. Fibronectin was localized by immunofluorescence in the extracellular matrix during the period of mesenchymal cell proliferation. During chondrogenesis, fibronectin was demonstrated in the differentiating chondrocytes. Fibronectin was detectable in the cartilage matrix only after hyaluronidase treatment. During vascular invasion, prior to osteogenesis, fibronectin was localized in association with endothelial cells. These observations demonstrate a possible role of fibronectin in collagenous matrix-mesenchymal cell interaction in vivo.
利用[35S]甲硫氨酸对大鼠体内基质诱导软骨内成骨过程中纤连蛋白的生物合成进行了研究。皮下植入以诱导局部骨形成的脱矿骨基质结合循环中的纤连蛋白。这可能是细胞附着于基质的一个重要初始条件。纤连蛋白在骨发育的整个过程中都存在，但在间充质细胞增殖和造血过程中占合成总蛋白的最大比例。通过以下方法在组织提取物中鉴定出纤连蛋白：(i) 在十二烷基硫酸钠/聚丙烯酰胺电泳凝胶上与人及大鼠血浆纤连蛋白共迁移；(ii) 对变性胶原的亲和力；(iii) 与大鼠血浆纤连蛋白纯化抗体的交叉反应性；(iv) 对胶原酶消化不敏感。在间充质细胞增殖期间，通过免疫荧光法将纤连蛋白定位在细胞外基质中。在软骨形成过程中，在分化的软骨细胞中发现了纤连蛋白。仅在透明质酸酶处理后，才能在软骨基质中检测到纤连蛋白。在血管侵入期间，在骨形成之前，纤连蛋白定位在内皮细胞周围。这些观察结果表明纤连蛋白在体内胶原基质-间充质细胞相互作用中可能发挥作用。
