FIG. 5.

Impairment of ENS development in Y1062F mutant mice. (A) Distribution pattern of enteric neurons in 15 homozygous Y1062F mutant mice. Bold solid lines indicate the region where the number of neurons was more than 50% of that in wild-type mice. Broken lines indicate the region with fewer neurons (less than 50% of the average number in wild-type mice). Six homozygous mutant mice (nos. 32, 33, 89, 105, 431, and 432) showed a complete absence of enteric neurons throughout the intestinal tract posterior to the stomach. The numbers above the lines in region 1 indicate the number of peripherin-positive ganglion cells (per section) in the intramuscular layer of the intestine. In all wild-type and heterozygous Y1062F mutant mice, ganglion cells were present from the stomach to the end of the colon (six wild-type and nine heterozygous mice were analyzed). The letters a to h represent the regions analyzed in panel B. (B) Immunohistochemical analysis of the intestinal tract with antiperipherin antibody. Representative sections of wild-type (a, b, and c) and homozygous Y1062F mice (d, e, f, g, and h) were stained with antiperipherin antibody. (a and d) stomach; (b, e, and g) small intestine; (c, f, and h) colon. Arrowheads denote peripherin-immunoreactive ganglion cells. In homozygous Y1062F mice, the ganglion cells in the small intestine and colon were absent (h) or their number and/or size were markedly reduced (e, f, and g). Bars, 50 μm. (C) Ret protein expression in Ret Y1062F knock-in mice. Total cell lysates (30 μg of protein) from the brain stem (br), stomach (st), small intestine (si), and colon (co) of wild-type (Wt), heterozygous (He), and homozygous (Ho) mutant mice were analyzed by Western blotting with anti-Ret antibody. The 175-kDa and 155-kDa Ret proteins are shown. Ret expression in the small intestine and the colon of homozygous Y1062F mice was noticeably reduced.