Fig. S1

Anti-Dlx3b and dlx5a^1073aEt support dlx3b and dlx5a gene expression patterns. (A) A diagram of dlx5a^j1073aEt. Transposon T2SKAG is inserted in the first exon of dlx5a, with GFP-coding sequence in opposite orientation from dlx5a. Thus, although this insertion generates a loss-of-function allele of dlx5a, it is not likely to produce a dlx5a:GFP fusion protein. Instead, 5′ RACE shows that GFP-containing transcripts initiate from a cryptic promoter site within the transposon sequence, suggesting that this weak promoter may allow the T2KSAG transposon to act as an enhancer trap, in this case revealing the activity of the enhancers driving dlx5a expression. (B-Y) Panels in the far left column are schematics of the views shown in confocal images. Skeletal abbreviations are as described in Fig. 1. Panels in the second-from-left column are merges of the single channel expression seen to the right. (C-E) Confocal projections at 36 hpf show that dlx5a^J1073aEt is expressed more broadly than Dlx3b immunolabeling. (G-I) Lateral (anterior leftwards, dorsal upwards) and (K-M) ventral (anterior leftwards, lateral upwards) confocal sections reveal that at 60 hpf dlx5a^J1073aEt still shows expression broader than Dlx3b immunolabel. Inferred skeletal element locations are indicated with broken yellow lines in single channel images. Gene expression outlines follow the color scheme shown in merged confocal images. (N-U) Projections of confocal stacks of ∼Col II/∼GFP label confirm dlx5a^J1073a expression within cartilage cells. (V-Y) Projections of confocal stacks showing GFP and Alizarin Red label at 6 dpf confirm dlx5a^J1073a expression within bones. All fish shown are heterozygous for dlx5a^J1073aEt. Scale bars: 100 μm.