Dynamic expression of sFRP3 in spinal cord and dorsal root ganglia at early embryo stages. A–E: Spinal cord sections from E9.5, E10.5, E11.5, E12.5, E13.5 were subjected to ISH with sFRP3 riboprobe. F: Scheme of VZ and DRG in spinal cord. sFRP3 expression was primarily detected in middle region of the spinal cord at E10.5. At E11.5, sFRP3 expression in ventricular zone (VZ) was expanded to the entire dorsal half of the spinal cord and observed in most of dorsal root ganglia (DRG). By E12.5, sFRP3 expression was down-regulated in dorsal VZ and DRG, but persisted in the middle VZ. Expression of sFRP3 in VZ is indicated by arrows, and its expression in DRG is outlined by black dashed lines. Scale bar = 50 μm.