Dynamic expression of p75 and Lingo-1 during development of mouse retinofugal pathway.

Our previous studies showed interaction of Nogo at the midline with its receptor (NgR) on optic axons plays a role in axon divergence at the mouse optic chiasm. Since NgR lacks a cytoplasmic domain, it needs transmembrane receptor partners for signal transduction. In this study, we examined whether the co-receptors of NgR, low-affinity neurotrophic receptor (p75) and Lingo-1, are localized on axons in the mouse optic pathway. In the retina, p75 and Lingo-1 were observed on neuroepithelial cells at E13 and later on the retinal ganglion cells at E14 and E15. At the optic disc, p75 was observed on the retinal axons, whereas Lingo-1 was found on glial processes surrounding the axon fascicles. Both p75 and Lingo-1 were found on axons in the optic stalk, optic chiasm and optic tract. Furthermore, a transient expression of Lingo-1 was observed on the SSEA-1 positive chiasmatic neurons at E13, but not at later developmental stages. The presence of p75 and Lingo-1 on optic axons provides further supports to the contribution of Nogo/NgR signaling in axon divergence at the mouse optic chiasm.