Kit^787F mice carrying a point mutation in c-Kit are MC-deficient. (A) Identification of the Kit^787F mutation. A single nucleotide transversion (A to T) results in 787F of the polypeptide chain. The sequence electropherograms of wild-type (wt), heterozygous animals (Kit^787F/+), and homozygous mutants (Kit^787F) genomic DNAs are shown in the upper panel. Cytospins (B) or sections of ear tissue (C) and trachea (D) from wild-type, heterozygotes (Kit^787F/+), or Kit^787F mice were subjected to toluidine blue staining (B-C) or naphtolesterase staining (D) and counterstained with hematoxylin. Photos were taken with a light microscope under 200× (C) or 400× (B,D) magnification. (E) Flow cytometric analysis of peritoneal MCs (c-Kit^high, T1/ST2^high). Percentages of double-positive cells are indicated. One representative experiment of 6 is shown.