Figure 1.
MAG inhibits NgR1-deficient postnatal CGNs. A, P7 CGNs isolated from wild-type (NgR1+/+; n = 5) and NgR1-deficient (NgR1−/−; n = 5) mice were cultured on CHO control or CHO-MAG feeder layers and stained with TuJ1. Scale bar, 50 μm. B, Quantification of neurite lengths on CHO (gray bars) and CHO-MAG cells (black bars) revealed strong inhibition of both wild-type and NgR1−/− neurons on CHO-MAG cells (p < 0.05). MAG inhibition is fully reversed in the presence of Y27632 [(R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide] (20 μm). The number of neurites quantified for each condition is indicated in parentheses. Results are presented as mean ± SEM from five independent experiments, and the percentile of neurite outgrowth compared with CHO controls is shown. No significant difference (n.s.) in neurite length is observed between wild-type and NgR1-deficient neurons cultured on CHO-MAG cells. Wild-type and NgR1−/− CGNs show robust and very similar growth on control CHO feeder cells [Kruskal–Wallis one-way ANOVA (post hoc Dunn's test)]. C, Western blot analysis for NgR1, NgR2, and p75NTR normalized to actin in P7 brain lysates of wild-type and NgR1 mutants. In wild-type brains, NgR1 protein is detected at an apparent molecular weight of 65 kDa. No NgR1 protein is detected in brain lysates of NgR1−/− mice. Loss of NgR1 does not result in altered expression levels of NgR2 or p75 protein.
