Immunohistochemistry (IHC) and mRNA in situ hybridization (ISH) were performed as previously described [13 (link), 14 (link)]. The following antibodies were used in immunohistochemistry: Sox2 (sc-17320, RRID: AB_2286684, 1:500; Santa Cruz Biotechnology), Olig2 (AF2418, RRID: AB_2157554, 1:100; R&D Systems; AB9610, AB_10141047,1:500; Millipore), CC1 (OP80, RRID:AB_213434, 1:200;Calbiochem), TCF7l2 (2569S, RRID: AB_2199816,1:200; Cell Signaling Technology; sc-8632, RRID: AB_2199825,1;100; Santa Cruz Biotechnology), PDGFRα (AF1062, AB_2236897,1:200; R&D System), EYFP (06-896, RRID: AB_310288, 1;500; Millipore), NG2 (AB5320, RRID:AB_91789, 1:200; Millipore), Ki67(9129, RRID: AB_10989986,1:200; Cell Signaling Technology), Sox10 (sc-17342, RRID: AB_2195374, 1:100; Santa Cruz Biotechnology), BrdU (sc-70441, RRID: AB_1119696, 1:100; Santa Cruz Biotechnology), APC (sc-896, RRID: AB_2057493,1:100; Santa Cruz Biotechnology). DyLight 488- or DyLight 549-conjugated secondary antibodies were from Jackson ImmunoResearch. Brdu, Edu (Click-iT EdU imaging kits, Invitrogen C10339) immunostaining were performed as previous study [13 (link), 14 (link)].