Figure 3

Smed-1H6 labels CNS and PNS axonal projections. (A-F) Whole-mount view of intact planarians immunostained with 1H6 (green) in conjunction with other antibodies or FISH to genes indicated in the panels. (A) 1H6 labels neural structures in the intact planarian. Arrows mark the anterior end of the ventral nerve cords (VNCs); closed arrowheads mark the VNCs near the pharynx. Open arrowheads highlight transverse and lateral axon branches. (B) Higher magnification image of 1H6 staining in the head region shows labeling in the anterior end of the VNCs (arrow) and in lateral branches (arrowhead). (C) 1H6 labels gpas ⁺ (magenta) brain branches in the head. Arrowheads denote one of the co-labeled branches. (D-F) Planarians double-labeled with1H6 and anti-SYNAPSIN (magenta). (D) High magnification shows that 1H6 labels neuronal projections in close association with SYNAPSIN⁺ synapses. (E) Co-labeling in the anterior region of the VNCs. (F) 1H6 staining is absent in the neuropil of the cephalic ganglia. Arrows point to examples of 1H6 and anti-SYNAPSIN co-labeling, whereas arrowheads (in F) mark the SYNAPSIN⁺ neuropil of the cephalic ganglia. (G) 1H6 labels many CRMP2⁺ (magenta) neurons in the intact planarian (shown in the head region, highlighted with arrowheads). (H) 1H6, 6G10 (magenta), and DAPI (blue, epidermal nuclei) labeling at the anterior tip of the worm demonstrates that 1H6 labels axon projections within the submuscular plexus. Arrowheads mark 1H6⁺ axons extending between epithelial cells. Images are maximum intensity projections of optical sections, except in A. Anterior is to the left in A, E, and F and to the top in B-D and G-H. Images were taken to the right side of the pharynx (facing the ventral side of the animal) in D and to the left side of the cephalic ganglia in C. Scale bars: (A) 200 μm; (B-G) 20 μm; (H) 50 μm.