Whole-mount immunohistochemistry on wild-type and homozygote embryos using 2H3 anti-neurofilament antibody showing the progression of cranial ganglion formation. (A,C) Wild-type and (B,D) mutant embryos at E9.5 and E10.5, respectively. Dorsal to the left, ventral to the right. Note the ganglion IX in two different stages of embryos. Arrows in A and C point to the nerve projections between the ninth ganglion and the hindbrain. Arrows in B and D point to the absence of nerve projection between the ninth ganglion and the hindbrain. The arrowheads in B and D point to the connections between ganglia IX and X. (V) Trigeminal ganglion; (VII) facial ganglion; (IX) glossopharyngeal ganglion; (X) vagus ganglion; (XI) accessory ganglion; (XII) hypoglossal nerve. ot, otic vesicle. Bar, 100 μm.