Spatially and temporally regulated expression of specific heparan sulfate epitopes in the developing mouse olfactory system

Abstract

Heparan sulfate (HS) comprises a structurally diverse group of glycosaminoglycans present ubiquitously on cell surfaces and in the extracellular matrix. The spatially and temporally regulated expression of specific HS structures is essential for various developmental processes in the nervous system but their distributions in the mouse olfactory system have not been explored. Here, we examined the spatiotemporal distribution of particular HS species in the developing mouse olfactory system using three structure-specific monoclonal antibodies (HepSS-1, JM403 and NAH46). The major findings were as follows. (i) During olfactory bulb morphogenesis, the HepSS-1 epitope was strongly expressed in anterior telencephalic cells and coexpressed with fibroblast growth factor receptor 1. (ii) In early postnatal glomeruli, the JM403 epitope was expressed at different levels among individual glomeruli. The expression pattern and levels of the JM403 epitope were both associated with those of ephrin-A3. (iii) In the vomeronasal system, the JM403 epitope was expressed in all vomeronasal axons but became increasingly restricted to vomeronasal axons terminating in the anterior region of the accessory olfactory bulb by 3 weeks of age. Our results demonstrate that each HS epitope exhibits a unique expression pattern during the development of the mouse olfactory system. Thus, each HS epitope is closely associated with particular developmental processes of the olfactory system and might have a particular role in developmental events.