Collagen XII mutation disrupts matrix structure of periodontal ligament and skin

Collagen XII has been postulated to organize the extracellular matrix (ECM) architecture of dense connective tissues such as the periodontal ligament (PDL) and skin. The objective of this study was to test this hypothesis in transgenic mice carrying a dominant interference mutation of collagen XII. The truncated alphaI(XII) collagen minigene construct MXIINC3(-), driven by the mouse alpha2(I) collagen promoter, was prepared and used to generate t ransgenic mouse lines. The PDL matrix fibers of molar teeth lost the ordere d architecture characteristic of ligament tissue without noticeable inflamm ation. Cellular cement appeared to be disrupted at the PDL insertion. By co nfocal laser scanning microscopy, the PDL of transgenic mice demonstrated s wollen and irregularly arranged collagen fibers associated with internal po rosity. The skill of transgenic mice revealed the lack of matrix fiber stru cture in the papillary dermis. These results indicated that the dominant in terference mutation of collagen XII disorganized the ECM architecture of PD L and skin.