Birk D E, Fitch J M, Babiarz J P, Linsenmayer T F
Department of Pathology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway 08854.
J Cell Biol. 1988 Mar;106(3):999-1008. doi: 10.1083/jcb.106.3.999.
The distribution, supramolecular form, and arrangement of collagen types I and V in the chicken embryo corneal stroma were studied using electron microscopy, collagen type-specific monoclonal antibodies, and a preembedding immunogold method. Double-label immunoelectron microscopy with colloidal gold-tagged monoclonal antibodies was used to simultaneously localize collagen type I and type V within the chick corneal stroma. The results definitively demonstrate, for the first time, that both collagens are codistributed within the same fibril. Type I collagen was localized to striated fibrils throughout the corneal stroma homogeneously. Type V collagen could be localized only after pretreatment of the tissue to partially disrupt collagen fibril structure. After such pretreatments the type V collagen was found in regions where fibrils were partially dissociated and not in regions where fibril structure was intact. When pretreated tissues were double labeled with antibodies against types I and V collagen coupled to different size gold particles, the two collagens colocalized in areas where fibril structure was partially disrupted. Antibodies against type IV collagen were used as a control and were nonreactive with fibrils. These results indicate that collagen types I and V are assembled together within single fibrils in the corneal stroma such that the interaction of these collagen types within heterotypic fibrils masks the epitopes on the type V collagen molecule. One consequence of the formation of such heterotypic fibrils may be the regulation of corneal fibril diameter, a condition essential for corneal transparency.
利用电子显微镜、I型和V型胶原特异性单克隆抗体以及包埋前免疫金法，研究了I型和V型胶原在鸡胚角膜基质中的分布、超分子形式及排列。使用胶体金标记的单克隆抗体进行双标记免疫电子显微镜，以同时在鸡角膜基质中定位I型和V型胶原。结果首次明确证实，两种胶原在同一原纤维中共分布。I型胶原均匀地定位于整个角膜基质的横纹原纤维中。只有在对组织进行预处理以部分破坏胶原原纤维结构后，才能定位V型胶原。经过这样的预处理后，V型胶原出现在原纤维部分解离的区域，而不是原纤维结构完整的区域。当用与不同大小金颗粒偶联的I型和V型胶原抗体对预处理后的组织进行双标记时，两种胶原在原纤维结构部分破坏的区域共定位。IV型胶原抗体用作对照，与原纤维无反应。这些结果表明，I型和V型胶原在角膜基质的单个原纤维中组装在一起，使得这些胶原类型在异型原纤维中的相互作用掩盖了V型胶原分子上的表位。形成这种异型原纤维的一个后果可能是角膜原纤维直径的调节，这是角膜透明所必需的条件。
