Fig. 1. Spinal cord olig2⁺ cells include diverse cell types. (A-H) Transverse sections of Tg[olig2:egfp] embryos. Antibodies indicated on each panel. (A) Twenty-four hpf embryo. Arrows indicate olig2:EGFP⁺, Isl⁺ motoneurons. (B) Thirty-six hpf embryo. Arrows and arrowheads mark olig2:EGFP⁺, Neurolin⁺ SMNs and olig2:EGFP⁺, Neurolin^- cells, respectively. (C) Forty-eight hpf embryo treated with BrdU from 36 to 48 hpf. Arrows mark olig2:EGFP⁺, BrdU⁺ cells (yellow). (D) Three dpf embryo. olig2:EGFP⁺ cells include Hu⁺ neurons (arrowheads), dorsally and ventrally migrated Hu^- OPCs (asterisks) and Hu^- cells with radial morphology (arrows). (E) Three dpf embryo. Arrows and arrowheads mark olig2:EGFP⁺, zrf-1⁺ radial cells. Asterisks mark dorsally migrated OPCs. (F) EGFP expression, alone, of section shown in E. (G,H) Twenty-four hpf embryo. Anti-GABA labeling reveals olig2:EGFP⁺ KA' and putative VeLD interneurons and olig2:EGFP^- KA'' interneurons. (I,J) Lateral confocal microscope images of 20 hpf (I) and 24 hpf (J) transgenic embryos showing olig2:EGFP⁺, GABA⁺ VeLD interneurons, olig2:EGFP⁺, GABA⁺ KA' interneurons and olig2:EGFP^-, GABA⁺ KA'' interneurons. Arrowheads in I mark descending axons of VeLD neurons. Scale bar: 20 µm.