A nonsense mutation in the ORF of <i>snapc4</i> is the <i>m1045</i> causal mutation.

<p>A) Schematic scheme of the zebrafish Snapc4 protein. The conserved Myb DNA binding domain and the interacting domains for Snapc1/snapc5 and Snapc2 as described for the human <i>SNAPC4</i> (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034671#pone.0034671-Ma1" target="_blank">[16]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034671#pone.0034671-Mittal1" target="_blank">[17]</a> are indicated by boxes. The m1045 mutation generates a premature stop codon in the zebrafish <i>snapc4</i> cDNA resulting in a truncated protein of 213 aa. The positions targeted by the MOe9i9 and MOi9e10 <i>snapc4</i> morpholinos are indicated with arrowheads. B) Genotyping of <i>m1045</i> mutant and unaffected sibling embryos by RFLP analysis. C–N) Phenotype of embryos injected with 8 ng of control morpholino, 8 ng of MOe9i9 or 6 ng of MOi9e10 <i>snapc4</i> morpholinos. C–E) Dorsal view of WISH performed with a trypsin probe of 3.5 dpf larvae: 84% of the control morphants display a complete extension of the pancreatic exocrine tail (n = 19) while 52% of MOe9i9 morphants show a drastic reduction of the pancreatic exocrine tail and 48% no extension at all (n = 19) and 9% of MOi9e10 morphants show a drastic reduction of the pancreatic exocrine tail and 91% no extension at all (n = 23). F–H) Lateral view of 3.5 dpf Ptf1∶GFP larvae: 95% of the control morphants display a complete extension of the pancreatic exocrine tail (n = 25) while 13% of MOe9i9 morphants show a drastic reduction of the pancreatic exocrine tail and 87% no extension at all (n = 83) and 24% of MOi9e10 morphants show a drastic reduction of the pancreatic exocrine tail and 62% no extension at all (n = 55). I–K) Alcian blue staining of 4 dpf embryos: MOe9i9 and MOi9e10 morphants display a reduction and malformation of the hyoid concomitant with the absence of the branchial arches 3 to 7. L–N) Confocal projections of the pancreatic region of embryos injected with Edu at 95 hpf and fixed at 96 hpf. All the control morphants show a high Edu incorporation rate (n = 15). 95% of the MOe9i9 morphants did not incorporate any Edu at all (n = 19) and 43% of the MOi9e10 morphants display no incorporation at all and 21% a considerably reduced incorporation rate (n = 14). Scale bars : 50 µm.