Changes in Distribution of the Long Form of Type XII Collagen during Chicken Corneal Development

Abstract

S U M M A R YThe expression and distribution of the long form of Type XII collagen were investigated histochemically during chicken corneal development using a monoclonal antibody (P3D11) raised against the N-terminal domain of chicken Type XII collagen. Specificity of the antibody was confirmed by immunoprecipitation before and after bacterial collagenase digestion. Immunofluorescent microscopic studies showed that during chicken cornea formation, the long form of Type XII collagen is initially detected on Day 3 embryo (stage 19) in the sub-epithelial matrix of the corneal periphery and in the matrix around the optic cup. On Day 5 embryo (stage 27) the long form was expressed in the primary stroma. Thereafter, as the secondary stroma was formed, the long form localized in the sub-epithelial and sub-endothelial matrices and in the anterior region of the limbus (corneoscleral junction) before the formation of Descemet's and Bowman's membranes. After hatching, the immunoreactivity decreased predominantly in the sub-epithelial and sub-endothelial matrices but remained at the anterior region of the limbus. Immunoelectron microscopic examination demonstrated that the long form localizes in the Descemet's and Bowman's membranes and along the collagen fibrils in the stroma with a periodic repeat. Based on the distribution of the long form of Type XII collagen in the sub-epithelial and sub-endothelial matrices and limbus, it was suggested that the long form of Type XII collagen is involved in formation of the Descemet's and Bowman's membranes and in stabilization of the limbus.

Mechanical Strain Increases Expression of Type XII Collagen in Murine Osteoblastic MC3T3-E1 Cells

“…Type XII collagen was mainly detected in the dense connective tissues including tendons, ligaments, dermis, cornea and membranous bones in developing chick and mouse (Oh et al, 1993;Gregory et al, 2001;Akimoto et al, 2002); however, in adult tissues, no information concerning its distribution has been reported. Here, we showed that mRNA corresponding to α1(XII) was predominantly expressed in the bone compared to other connective tissue-rich organs, e.g.…”

“…Type XII collagen α1 chain (α1(XII)) is encoded by a single gene, and differential splicing within NC3, one of the collagenase-resistant globular domains in the amino terminus of the α1(XII), results in a long and a short variant. The long form can carry a glycosaminoglycan (Koch et al, 1995) and is detected as early as Day 3 embryo of chick (Akimoto et al, 2002). It was reported that the NC3 domain of α1(XII) could modulate the biomechanical properties of collagen gel contraction in vitro (Nishiyama et al, 1994), and interacted with decorin and fibromodulin (Font et al, 1996;Font et al, 1998) and tenascin-X (Veit et al, 2006b).…”

Regulation of corneal stroma extracellular matrix assembly

“…The fibril-associated collagens detected in mammalian corneas include collagens XII and XIV (Akimoto et al, 2002; Gordon et al, 1996; Marchant et al, 2002; Young et al, 2002). In the avian cornea, collagen IX also has been implicated (Akimoto et al, 2002; Fitch et al, 1998; Fitch et al, 1994; Young et al, 2002).…”

“…In the avian cornea, collagen IX also has been implicated (Akimoto et al, 2002; Fitch et al, 1998; Fitch et al, 1994; Young et al, 2002). FACIT collagens have several short collagenous (COL) domains interrupted by non-collagenous (NC) domains.…”

Collagens and proteoglycans of the cornea: importance in transparency and visual disorders

“…Among them, the FACITs are characterized by the alternation in their structure of typical collagen triple-helical domains and non-collagen domains, the latter including known matrix protein motifs (Akimoto et al 2002). These collagens are not able to form collagen fibrils by themselves.…”