NCSCs were detached using Accutase and counted, and 1 × 106 cells per experimental condition were fixed in 4% paraformaldehyde and then blocked in 10% bovine serum albumin. Cells were incubated for 1 hour with primary antibodies conjugated to fluorophores (HNK1–fluorescein isothiocyanate and nerve growth factor receptor–Alex Fluor 647; BD Biosciences). Analyses were performed on a FACSCalibur instrument (BD Biosciences), and data were analyzed with FCS express software (Tree Star). Fluorescence-activated cell sorting characterization for 7dupASD3 and CTL4R lines is reported in fig. S1B; for all the other lines, see (16).