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Repulsive guidance cues can steer neuronal growth cones during development and prevent mature axons from regenerating. We have identified a 100 kd glycoprotein in the chick brain that is a good candidate for a repulsive cue. Since it induces the collapse and paralysis of neuronal growth cones in vitro, we have named it collapsin. It is effective at(More)
During embryogenesis, different subclasses of sensory neurons extend central projections to specific locations in the spinal cord. Muscle and cutaneous afferents initially project to the same location in the dorsal cord. Later, specific muscle afferents leave other afferents behind and project into the ventral cord. Previous studies have shown that ventral(More)
The present study explores the role of SEMA3A (collapsin-1) in the temporal and spatial regulation of developing sensory projections in the chick spinal cord. During development, SEMA3A mRNA (SEMA3A) is first expressed throughout the spinal gray matter, but disappears from the dorsal region when small caliber (trkA(+)) sensory axon collaterals first grow(More)
Collapsin-1 is a member of the semaphorin family of signaling molecules that acts as a repellent for growing spinal sensory axons. We have constructed a chimeric collapsin-1/alkaline phosphatase probe to visualize putative collapsin-1 receptors in vitro and in situ. As predicted by the activity profile of collapsin-1, the probe binds spinal sensory tracts,(More)
The vertebrate retina develops from a sheet of neuroepithelial cells. Because adherens and tight junctions are critical for epithelial and neuronal differentiation in a variety of eukaryotic systems, we examined the role of Par-3, a PDZ scaffold protein that is critical in cellular membrane junction formation. We cloned the zebrafish Par-3 ortholog (pard3),(More)
Collapsin-1 is a secreted glycoprotein that inhibits the extension of specific growth cones in vitro. It has been hypothesized to serve as a repulsive guidance cue for extending growth cones in vivo. Here we report the distribution of collapsin-1 message as demonstrated by in situ hybridization using digoxigenin-labeled RNA probes in wholemounts and tissue(More)
Foxe3 is a winged helix/forkhead domain transcription factor necessary for mammalian and amphibian lens development. Human FOXE3 mutations cause anterior segment dysgenesis and cataracts. The zebrafish foxe3 cDNA was PCR amplified from 24 h post-fertilization (hpf) embryo cDNA. The zebrafish foxe3 gene consists of a single exon on chromosome 8 and encodes a(More)
Recent advances in the identification of factors that inhibit axon extension lead us to suggest that there exist at least two functionally distinct categories of inhibitory factors: those that inhibit the motile apparatus of the growth cone, and those that destabilize interactions of the growth cone with the substratum. These two types of inhibitory factors(More)
Most axons in the CNS innervate specific subregions or layers of their target regions and form contacts with specific types of target neurons, but the molecular basis of this process is not well understood. To determine whether collapsin-1/semaphorin-III/D, a molecule known to repel specific axons, might guide afferent axons within their cerebellar targets,(More)
The vertebrate retina develops from an undifferentiated sheet of neuroepithelial cells, whose differentiation requires the generation and maintenance of the correct cellular polarity. To examine the role of cell polarity in retinal development, we cloned three zebrafish lin7 genes (lin7a, lin7b, and lin7c), which each encodes a protein candidate that is(More)