Figure 3
SIX1 is crucial during mouse dorsal root ganglia development. (A-D) Immunofluorescence of SIX1 (green), neuronal marker ISL1/2 (magenta) and glial marker SOX10 (magenta) in dorsal root ganglia (DRG) of embryonic day (E) 11.5 Six1/4+/EGFP embryos, in which the Six1-locus directs the expression of enhanced GFP (EGFP; green). (E-P) Abnormalities in Six1/4EGFP/EGFP DRG. (E,F) Arrowheads: ISL1/2 (green)- and SOX10 (magenta)-double-positive cells; arrows: ventrally located ISL1/2-positive cells (F), which were never observed in Six1/4+/EGFP at E11.5 (E). (G,H) Coronal sections of lumbar region at E14.0 (top: rostral side). DRG are fused over several segments in Six1/4EGFP/EGFP embryos (square bracket in H), but segmented in Six1/4+/EGFP (arrows in G). (I-P) Transverse sections of dorsal spinal cords (sc) at E11.5. Arrowheads: intramedullary EGFP (green)-, ISL1/2 (magenta)- and NTRK3 (magenta)-triple-positive cells only in Six1/4EGFP/EGFP; arrows: EGFP-positive afferents at the dorsal root entry zone. Dashed lines demarcate the position of ectoderm and sc. Scale bars: 200 μm (G,H) and 50 μm (A-F,I-P).