Smed-1D9 labels the CNS and neoblast progeny. (A-D) Whole-mount view of intact planarians or regenerating planarians immunostained with 1D9 (green), and counterstained with DAPI (blue) in B and stained with anti-SMEDWI (magenta) in E-F. (A) 1D9 staining in the intact planarian reveals labeling surrounding the cephalic ganglia (arrows) and ventral nerve cords (arrowheads), and in the mesenchyme. Dashed boxes indicate the regions shown in E (white), and F (yellow). (B) Higher magnification image of the cephalic ganglia demonstrates that 1D9 labels the nucleus (counterstained with DAPI). (C, D) 1D9 labels the anterior and posterior blastema during regeneration in 2, 3, 4, 5, and 7 dpa trunk regenerates. The morphology of the nascent cephalic ganglia is apparent by 4 dpa (indicated by arrowheads). (D) View of the anterior regeneration blastema. (E) Image of the area proximal to the posterior end of the cephalic ganglia in an intact planarian shows a large population of 1D9+ cells co-labeled with anti-SMEDWI. (F) Image of the area immediately posterior to the pharynx showing the presence of 1D9+ cells co-labeled with anti-SMEDWI. Dashed boxes indicate the area shown in the insets. Images are maximum intensity projections of optical sections except for A and C. Anterior is to the top in all images. Scale bars: (A) 200 μm; (B, D-F) 50 μm; (C) 100 μm.