Fig. 3

Gli-dependent patterning in the absence of Smo. (A-L) Zebrafish embryos obtained from wild-type, gli2a^ty17/+ or gli1^ts269/+ incrosses (18 hpf) were treated with either ethanol (EtOH) or 100 μM cyclopamine and stained for ptc1 or isl2a transcripts. The trunk region between approximately the third and twelfth somites is shown laterally, anterior to the left. Arrowheads in D-F show basal ptc1 expression in the neural tube; arrowheads in H,I show disorganized PMNs in gli2a^ty17/ty17 and gli1^ts269/ts269 embryos. (M) Quantification of PMNs in wild-type embryos and those resulting from incrosses of gli2a^ty17/+ or gli1^ts269/+ zebrafish after treatment with either ethanol or 100 μM cyclopamine. Homozygous gli2a^ty17 and gli1^ts269 mutants were identified by the absence of hindbrain cranial motoneurons, which cannot be assessed after cyclopamine treatment. ^*, P<0.05; ^***, P<0.001; n.s., not significant. Bar indicates the mean. (N) Quantification of PMNs in MZsmo embryos treated as indicated. Error bars represent s.e.m. ^***, P<0.001, compared with control MZsmo embryos. Scale bar: 100 μm.