Linsenmayer T F, Gibney E, Schmid T M
Dev Biol. 1986 Feb;113(2):467-73. doi: 10.1016/0012-1606(86)90182-x.
To determine whether short-chain cartilage collagen, collagen type X, is a component of notochordal matrix, we have performed immunohistochemistry with a monoclonal antibody (X-AC9) previously shown to be specific for this molecule (Schmid and Linsenmayer (1984). J. Cell Biol. 100, 598-605). We have also examined different stages of embryos to establish the temporo-spatial appearance of the molecule. The data show that type X collagen is indeed a component of notochordal matrix, but that its developmental appearance is quite late compared to that of type II collagen, another cartilage matrix molecule found in notochord. It is detected only in embryos older than 12 days. The appearance of type X collagen within the notochord is preceded by its appearance within the surrounding hypertrophic cartilage matrix of the vertebral bodies. Spatially, within the notochord the appearance of type X collagen is initially restricted to sites at which the surrounding vertebral cartilage matrix is also reactive for type X. With subsequent development, the notochordal reactivity extends, in a decreasing gradient, anteriorly and posteriorly toward the intervertebral zones. However, the brightest immunofluorescence of notochordal type X is maintained at the midvertebral sites. The ultimate fate of the notochordal tissue at such midvertebral sites is to be removed during endochondral bone formation within the vertebrae. We have observed that type II collagen is also found within notochordal tissue, but this molecule has a distribution which is the converse of that of the type X collagen. The type II collagen is preferentially deposited at intervertebral sites (i.e., the locations of future intervertebral discs). That the type X collagen within the notochord is preferentially deposited at sites destined to be replaced is consistent with one of the hypotheses we previously raised for the function of the type X collagen molecule--it may "target" skeletal tissues for eventual removal.
为了确定短链软骨胶原蛋白（X型胶原蛋白）是否为脊索基质的组成成分，我们使用了一种单克隆抗体（X-AC9）进行免疫组织化学实验，该抗体先前已被证明对这种分子具有特异性（施密德和林森迈尔，1984年。《细胞生物学杂志》100卷，598 - 605页）。我们还研究了胚胎的不同阶段，以确定该分子的时空出现情况。数据表明，X型胶原蛋白确实是脊索基质的组成成分，但与II型胶原蛋白相比，其发育出现时间相当晚，II型胶原蛋白是在脊索中发现的另一种软骨基质分子。它仅在12天以上的胚胎中被检测到。X型胶原蛋白在脊索内出现之前，先在椎体周围的肥大软骨基质中出现。在空间上，在脊索内，X型胶原蛋白的出现最初局限于周围椎体软骨基质对X型也有反应的部位。随着后续发育，脊索的反应性以递减梯度向前和向后延伸至椎间区域。然而，脊索X型的最亮免疫荧光在椎体中部位置保持。在椎体软骨内骨形成过程中，椎体中部这些部位的脊索组织最终会被去除。我们观察到，II型胶原蛋白也存在于脊索组织中，但这种分子的分布与X型胶原蛋白相反。II型胶原蛋白优先沉积在椎间部位（即未来椎间盘的位置）。脊索内的X型胶原蛋白优先沉积在注定要被替换的部位，这与我们之前提出的关于X型胶原蛋白分子功能的一个假设一致——它可能“靶向”骨骼组织以便最终被去除。
