Fig. 2

Fig. 2 Ret regulates enteric neuron colonization of the gut in a dose-dependent manner. (A–D) Zebrafish injected with translation blocking antisense morpholino oligos against ret ret MO at the one- to two-cell stage are analyzed for the presence of Hu-expressing enteric neurons at 4dpf. Compared to control morpholino injected fish that possess enteric neurons along the full length of the gut tube (A), zebrafish injected with 6 ng retMO show an absence of enteric neurons throughout the majority of the gut tube (B). While injection of 1 ng retMO has no apparent effect on enteric neurons (C), injection of 3 ng of retMO leads to partial phenotypes, with enteric neurons absent from only the distal most gut regions (compare (D) to (B) and (C)). Asterisk indicates the end of gut tube. Arrows indicate distal most enteric neurons. All panels show lateral views. Images for comparison are photographed at the same magnification.