(A) Dot plot indicating expression of general fast and slow MN functional subtype markers. Light blue dot next to gene name indicates a transcription factor. At 2 dpf, uts2d is expressed by a small number of MNs.
(B) Top: antibody stain demonstrating domain of Mnx (Hb9) expression within mature MNs in Tg(olig2::GFP) larvae at 2 dpf. Bottom: schematic indicating general domains of expression considered when verifying functional subtype expression. Dorsal GFP+ cells are putative fast MNs (blue), most ventral are progenitors or oligodendrocytes (green), and those between are putative slow MNs (gray).
(C–J) FISH and feature plots for MN subpopulation markers at 2 dpf. Gold arrow indicates dorsoventral localization of FISH expression within MN population. Dotted line indicates ventral spinal cord boundary. Left image (L) is lateral view, and right image (T) is transverse view. Scale bars, 10 μm.