Collagen fibrillogenesis in vitro: interaction of types I and V collagen regulates fibril diameter

• Published in: Journal of cell science Vol. 95; no. 4; pp. 649 - 657
• Main Authors: BIRK, D. E, FITCH, J. M, BABIARZ, J. P, DOANE, K. J, LINSENMAYER, T. F
• Format: Journal Article
• Language: English
• Published: Cambridge Company of Biologists 01-04-1990
• Subjects: Animals; Antibodies, Monoclonal; Biological and medical sciences; Cell structures and functions; Chick Embryo; chickens; collagen; Collagen - isolation & purification; Collagen - metabolism; Connective Tissue - metabolism; Connective Tissue - ultrastructure; cornea; Cornea - metabolism; Cornea - ultrastructure; Electrophoresis, Polyacrylamide Gel; fibrils; formation; Fundamental and applied biological sciences. Psychology; Immunohistochemistry; In Vitro Techniques; interaction; isoforms; Miscellaneous; Molecular and cellular biology; Polymers; regulation; Vertebrata; Cornea; Embryo; Regulation(control); Collagen; Morphology; Molecular interaction; Immunoelectron microscopy; Glycoproteins; Chicken; Aves; Fibril
• ISSN: 0021-9533; 1477-9137
• DOI: 10.1242/jcs.95.4.649

The small-diameter fibrils of the chick corneal stroma are heterotypic, composed of both collagen types I and V. This tissue has a high concentration of type V collagen relative to other type I-containing tissues with larger-diameter fibrils, suggesting that heterotypic interactions may have a regulatory role in the control of fibril diameter. The interactions of collagen types I and V were studied using an in vitro self-assembly system. Collagens were purified from lathyritic chick embryos in the presence of protease inhibitors. The type V collagen preparations contained higher molecular weight forms of the alpha 1(V) and alpha 2(V) chains constituting 60-70% of the total. Rotary-shadow electron micrographs showed a persistence of a small, pepsin-sensitive terminal region in an amount consistent with that seen by electrophoresis. In vitro, this purified type V collagen formed thin fibrils with no apparent periodicity, while type I collagen fibrils had a broad distribution of large diameters. However, when type I collagen was mixed with increasing amounts of type V collagen a progressive and significant decrease in both the mean fibril diameter and the variance was observed for D periodic fibrils. The amino-terminal domain of the type V collagen molecule was required for this regulatory effect and in its absence little diameter reducing activity was observed. Electron microscopy using collagen type-specific monoclonal antibodies demonstrated that the fibrils formed were heterotypic, containing both collagen types I and V. These data indicate that the interaction of type V with type I collagen is one mechanism modulating fibril diameter and is at least partially responsible for the regulation of collagen fibril formation.