Distinct expression of type XIII collagen in neuronal structures and othertissues during mouse development

Type XIII collagen is a type II transmembrane protein found in adhesive str uctures of mature tissues. We describe here its expression and spatio-tempo ral localization during mouse fetal development. Type XIII collagen mRNAs w ere expressed at a constant rate during development, with an increase of ex pression towards birth. Strong type XIII collagen expression was detected i n the central and peripheral nervous systems of the developing mouse fetus in mid-gestation. Cultured primary neurons also expressed this collagen, an d it was found to enhance neurite outgrowth. The results suggest that type XIII collagen is a new member among the proteins involved in nervous system development. Strong expression during early development was also detected in the heart, with localization to cell-cell contacts and accentuation in t he intercalated discs perinatally. During late fetal development, type XIII collagen was observed in many tissues, including cartilage, bone, skeletal muscle, lung, intestine and skin. Clear developmental shifts in expression suggest a role in endochondral ossification of bone and the branching morp hogenesis in the lung. Notable structures lacking type XIII collagen were t he endothelia of most blood vessels and the endocardium. Its initially uniq ue staining pattern began to concentrate in the same adhesive structures wh ere it exists in adult tissues, and started to resemble that of the beta1 i ntegrin subunit and vinculin during late intrauterine development and in th e perinatal period. (C) 2001 Elsevier Science B.V./International Society of Matrix Biology. All rights reserved.