Collagen fibrillogenesis in situ: Fibril segments undergo post‐depositional modifications resulting in linear and lateral growth during matrix development
Tóm tắt
Elucidating how collagen fibril growth is regulated is important in determining how tissues are assembled. Fibrils are deposited as segments. The growth of these segments is an important determinant of tissue architecture, stability, and mechanical attributes. Fibril segments were isolated from developing tendons and their structure characterized. The post‐depositional changes leading to linear and lateral growth of fibrils also were examined. Segments extracted from 14‐day chicken embryo tendons had a mean length of 29 μm. The segments were asymmetric, having a short and a long tapered end. Most of the segments were centrosymmetric with respect to molecular packing. Segments extracted from 12‐to 16‐day tendons had the same structure, but mean segment length increased incrementally due to the addition of an increasingly large population of longer segments. At 17 days of development there was a precipitous increase in segment length. The morphological data indicate that the increase in length was the result of lateral associations among adjacent segments. Analysis demonstrated that this fibril growth was associated with a significant decrease in fibril associated decorin. Using immunoelectron microscopy, decorin was seen to decrease significantly at 18 days of development. When decorin content was biochemically determined, a decrease also was observed. Decorin mRNA also decreased relative to fibrillar collagen mRNA during the same period. These data support the hypothesis that a decrease in fibril‐associated decorin is necessary for fibril growth associated with tissue maturation. Growth through post‐depositional fusion allows for appositional and intercalary growth and would be essential for normal development, growth, and repair. © 1995 Wiley‐Liss, Inc.
Từ khóa
Tài liệu tham khảo
Birk D. E., 1994, Collagen fibril assembly, deposition and organization into tissue specific matrices, 91
Gordon M. K., 1994, Type V collagen and Bowman's membrane: Quantitation of mRNA in epithelium and stroma, J. Biol. Chem., 269, 24959, 10.1016/S0021-9258(17)31483-7
Hahn R. A., 1992, B‐D xyloside alters dermatan sulfate proteoglycan synthesis and the organization of the developing avian corneal stroma, Development, 115, 383, 10.1242/dev.115.2.383
Hart G. W., 1976, Biosynthesis of glycosaminolgycans during corneal development, J. Biol. Chem., 251, 6513, 10.1016/S0021-9258(17)32977-0
Nimni M. E., 1988, Collagen, 1
Ninomiya Y., 1984, Synthesis and characterization of cDNA encoding a cartilage‐specific short collagen, Trends. Pharmacol. Sci., 81, 3014
Trelstad R. L., 1984, Extracellular Matrix in Development, 513
Trotter J. A., 1989, The length of collagen fibrils in tendon, Orthoped. Res. Soc., 35, 180a
Veis A., 1988, Collagen, 113