Dennis M. Snow

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In vivo studies of the roof plate of the spinal cord and midline optic tectum in rodent and the developing subplate in the telencephalon of the chick showed that two glycosaminoglycans, keratin sulfate and chondroitin sulfate, possibly in the proteoglycan form (KS-PG, CS-PG, or KS/CS-PG), were present at times when axons approach closely but do not invade(More)
Certain types of glial structures, located at strategic positions along axon pathways, may provide the mechanical and/or chemical elements for the construction of barriers which can grossly direct the elongation of axons during development. The roof plate, a putative axon barrier, is located along the dorsal midline of the developing spinal cord and may be(More)
Sulfated proteoglycans (PGs) may play a significant role in the regulation of neurite outgrowth. They are present in axon-free regions of the developing nervous system and repel elongating neurites in a concentration-dependent manner in vitro. The addition of growth-promoting molecules, such as laminin, can modify the inhibitory effect of PGs on neurite(More)
In the developing retina, retinal ganglion cell (RGC) axons elongate toward the optic fissure, even though no obvious directional restrictions exist. Previous studies indicate that axon-matrix interactions are important for retinal ganglion cell axon elongation, but the factors that direct elongation are unknown. Chondroitin sulfate proteoglycan (CS-PG), a(More)
Growth cone turning is an important mechanism for changing the direction of neurite elongation during development of the nervous system. Our previous study indicated that actin filament bundles at the leading margin direct the distal microtubular cytoskeleton as growth cones turn to avoid substratum-bound chondroitin sulfate proteoglycan. Here, we(More)
The primary mediators of cell migration during development, wound healing and metastasis, are receptors of the integrin family. In the developing and regenerating nervous system, chondroitin sulfate proteoglycans (CSPGs) inhibit the integrin-dependent migration of neuronal growth cones. Here we report that embryonic sensory neurons cultured on the(More)
The differentiation and morphogenesis of neural tissues involves a diversity of interactions between neural cells and their environment. Many potentially important interactions occur with the extracellular matrix (ECM), a complex association of extracellular glycoproteins organized into aggregates and polymers. In this article, we discuss recent findings on(More)
A variety of molecular influences in the extracellular matrix (ECM) interact with developing axons to guide the formation of hippocampal axon pathways. One of these influences may be chondroitin sulfate proteoglycans (CSPGs), which are known to inhibit axonal extension during development and following central nervous system injury. In this study, we(More)
The extracellular matrix through which growth cones navigate contains molecules, such as chondroitin sulfate proteoglycan, that can inhibit growth cone advance and induce branching and turning. Growth cone turning is accompanied by rearrangement of the cytoskeleton. To identify changes in the organization of actin filaments and microtubules that occur as(More)