Identification, cDNA cloning, and expression analysis of dermatopontin in the goldfish Carassius auratus

Abstract

Fish scales are a potential source of collagen for fabricating scaffolds for cells during tissue engineering because fish collagen has a low risk of zoonosis. Since the assembly of collagen fibrils has a significant impact on the functionality of the scaffold, the ability to replicate the fibril assembly of human tissues is critical. To determine the mechanism of fish collagen fibril assembly, we first identified non-collagenous proteins (NCPs), the potential regulators of fibril assembly in vivo, and then used tandem mass spectrometry to analyze the NCPs contained in the basal plates of goldfish Carassius auratus scales, a collagenous plate which is characterized by a plywood-like assembly of collagen fibrils similar to that found in the cornea. We identified a 19-kDa acidic protein as dermatopontin, the NCP which is a possible regulator of fibril assembly in the mammalian cornea. We cloned a goldfish dermatopontin cDNA of 1,074 bp containing an open reading frame encoding 196 amino acids. Reverse transcription-PCR revealed that dermatopontin mRNA was expressed in a wide range of tissues, including scale, skin, fin, eye, and skeletal muscle. In situ hybridization revealed that dermatopontin mRNA was expressed primarily in the basal plate-producing hyposquamal scleroblasts of the scales, suggesting that the dermatopontin is linked to the collagen fibril assembly of the basal plate.