DEVELOPMENTAL REGULATION OF DECORIN EXPRESSION IN POSTNATAL RAT-BRAIN

Here, we report on the expression of the small chondroitin/dermatan su lfate proteoglycan decorin in the developing postnatal rat brain. Nort hern analysis of brain RNA demonstrated decorin transcripts with peak expression on postnatal day 3 followed by a slow decline to the lower adult level. In situ hybridization and immunohistochemistry revealed p ostnatal decorin expression in the grey matter of neocortex, hippocamp us and thalamus, in myelinated fibre tracts and in several mesenchymal tissues (blood vessels, pia mater and the choroid plexus). In the neo cortex, decorin is expressed in a specific laminar pattern with intens e staining of the cortical plate and its derivatives, which differs re markably from the distributions observed for other proteoglycans [B. M iller, A.M. Sheppard, A.R. Bicknese, A.L. Pearlman, Chondroitin sulfat e proteoglycans in the developing cerebral cortex: the distribution of neurocan distinguishes forming afferent and efferent axonal pathways, J. Comp. Neurol. 355 (1995) 615-28]. Thus, decorin seems to serve yet unknown functions in the developing a rat brain parenchyma in additio n to its well-established role as a constituent of the mesenchymal ext racellular matrix. (C) 1998 Elsevier Science B.V. All rights reserved.