Figure 3

Figure 3

Functional analysis of ret morphants and mutants. (A) Phenotypical variability observed in zebrafish, using MO targeting Ret expression and two different zebrafish ret mutant lines. Proposed phenotyping classifications are shown by microscopy images and illustrations. Scale bar represents 200 μm. (B) Microscopic images of Tg(−8.3phox2bb:keade) zebrafish injected with control or ret MO, show normal ENS colonization in controls and a total colonic HSCR phenotype in the ret MO injected fish. Peristaltic function is disrupted in zebrafish lacking enteric neurons, which is shown by the absence of bowel movement in the STMaps. Scale bar represents 200 μm. Note that the use of the terms hypoganglionosis and HSCR in zebrafish despite the lack of ganglia in this organism, refers to the reminiscent phenotype observed in mammals (humans).