Fig. 1

lmx1b expression in zebrafish spinal cord. a Three-class ANOVA comparison of V0v cells (class 3), trunk cells (class 1) and all post-mitotic neurons (class 2). p values test hypothesis that there is no differential expression among the 3 classes. Columns represent individual microarray experiments. Rows indicate relative expression levels as normalized data, subjected to a Z-transformation where mean = 0 and standard deviation = 1, where red = normalized expression value of +1 and blue = normalized expression value of -1 (see Methods for more details). lmx1ba and lmx1bb are expressed by V0v neurons. Positive control evx1 is also expressed by V0v neurons. Negative controls eng1b and myod1 are expressed by other neurons (V1 cells) and trunk cells respectively. ²actin is a housekeeping gene that is expressed by all populations. b-l Lateral views of zebrafish spinal cord at 27 h (b and c), 30 h (h-l), 36 h (d and e) and 48 h (f and g). Anterior left, dorsal top. in situ hybridization for lmx1ba (b, d and f) and lmx1bb (c, e and g). Black dashed line (b-g) is just below ventral limit of spinal cord, floor plate is right above this, in the most ventral part of the spinal cord, roof plate is the most dorsal part of the spinal cord. Double in situ hybridization for lmx1bb (red) and lbx1a (green) in WT embryo, merged view (h) and magnified single confocal plane of white dotted box region (h′-h′′′). in situ hybridization for lmx1bb (red) and EGFP immunohistochemistry (green) in Tg(evx1:EGFP) ^SU1 embryo, merged view (i) and magnified single confocal plane of white dotted box region (i′-i′′′). Double in situ hybridization for lmx1bb (red) and slc17a6 (green) in WT embryo, merged view (j) and magnified single confocal plane of white dotted box region (j′-j′′′). in situ hybridization for lmx1bb (red) and EGFP immunohistochemistry (green) in Tg(slc17a6:EGFP) embryo, merged image (k) and magnified single confocal plane of white dotted box region (k′-k′′′). White dashed line (k) marks the dorsal limit of the spinal cord. Red staining above the dashed line is outside the spinal cord. Double in situ hybridization for lmx1bb (red) and slc32a1 (green) in WT embryo, merged image (l) and magnified single confocal plane of white dotted box region (l′-l′′′). In all cases (h-l) * indicates co-labeled cell, x indicates single labeled lmx1bb-expressing cell. In all cases, at least two independent double-labeling experiments were conducted (h-l). Results were similar for each replicate. Numbers of single and double-labeled cells and number of embryos counted are provided in Tables  1 and 2. Scale bar = 50 µm (b-g), 70 µm (h-l) and 20 µm (h′-l′′′)