Fetal glial cells progenitors were extracted from 17 to 22-week-old human fetuses obtained at abortion. The forebrain ventricular and subventricular zones were dissected free on ice and then were dissociated using papain/DNAase as described (Windrem et al., 2004). All samples were obtained with consent under approved protocols of the University of Rochester Research Subjects Review Board. Glial progenitor cells were isolated by magnetic activated cell sorting, as described in Supplementary Methods. In addition, murine A2B5+/PSA-NCAM- cells were identically prepared from newborn Tg(CAG-EGFP)B5Nagy/J pups (Jackson Laboratory).
