SPACRCAN in the developing retina and pineal gland of the rat: Spatial andtemporal pattern of gene expression and protein synthesis

SPACRCAN is a hyaluronan-binding proteoglycan that is present in the pineal gland and interphotoreceptor matrix of the retina. Here, we evaluate the p attern of SPACRCAN gene expression and protein appearance during retinal an d pineal gland development in the rat. In situ hybridization histochemistry with SPACRCAN riboprobes indicates that hybridization signals are first ev ident in the retina over developing photoreceptor cells at embryonic day 16 (E16) and in the pineal gland at E21. Immunocytochemistry using a SPACRCAN antibody shows localization of SPACRCAN protein in the developing interpho toreceptor matrix by Postnatal day 5 (P5) and in the pineal gland by P6. Th ese studies suggest that SPACRCAN mRNA expression may occur substantially e arlier than the time when SPACRCAN protein is detectable in both the retina and the pineal gland. The period of retinal histogenesis when SPACRCAN is detected first is coincident with the time photoreceptors begin to extend f rom the outer retinal surface, suggesting that SPACRCAN may participate in the maturation and maintenance of the light-sensitive photoreceptor outer s egment, (C) 2001 Wiley-Liss, Inc.