Extended Data Fig. 2: Design and in vivo characterization of the cell type specificity of ChatE.

a, Schematic of ATAC-seq data from² showing accessibility of ChatE (pink) in spinal motor neurons over time. b, Design of ChatE constructs. c, Schematic of the 1000 bp ChatE demonstrating the presence of transcription factor binding motifs enriched during motor neuron specification or maturation. d,e, Quantification and representative images of mCherry distribution across spinal cord and dorsal root ganglia (DRG) sections from n = 3 mice injected with low titer AAV-mCherry (3.19E + 10 vg/animal) at P1 and analyzed at P45. In D, tissues from the same animal were used to quantify the incidence of mCherry+ cells across the indicated cell types. Circles represent females; triangles represent males. In E, whole cord images were taken at 5x on an epifluorescence microscope (scale bar = 200 µm). Unfilled arrowhead indicates V0c interneurons; dashed lines indicate PGCs represented in inset. PGC inset images were taken at 40x on a confocal microscope are maximum projections of 7 z sections taken 3 µm apart (scale bar = 20 µm). DRG images were taken at 20x on an epifluorescence microscope (scale bar = 200 µm). Filled arrowhead indicates mCherry+ sensory neuron. f, Representative 5x epifluorescence images of whole L4-L5 spinal cord sections from n = 2 animals injected at P1 with low titer AAV-NLS-GFP (2.10E + 10 vg/animal). Dashed yellow line indicates region shown in inset.