Fig. 1.

Brush cells are eliminated in the GI tract of Skn-1 KO mice.

(a) Tissue distribution of Skn-1a. RT-PCR analysis revealed that Skn-1a was abundantly expressed in the circumvallate papillae, stomach, duodenum, jejunum, and ileum but absent or only faintly expressed in all other tissues examined, including the pancreas, islets of Langerhans, brain, liver, skeletal muscle, white adipose tissue (WAT), and brown adipose tissue (BAT).

(b) Immunostaining revealed strong Skn-1a signals in the corpus beneath the limiting ridge in the stomach (upper panel) and in a subset of cells in the small intestine (lower panel). Inset in the upper right corner of each panel shows higher magnification image of the area enclosed by the dashed box.

(c) In situ hybridization revealed that Trpm5 mRNA was expressed in the jejunum of WT mice (upper panel) but not in Skn-1 KO mice (lower panel).

(d) Immunostaining revealed Dclk1 signals in WT mice (upper panel) but not Skn-1 KO mice (lower panel). The arrowheads indicate signals.

(e) Double immunostaining demonstrated that nearly all Trpm5-positive cells were also positive for Skn-1a. The arrows indicate cells expressing Trpm5 and Skn-1a. Scale bars: 100 μm and 25 μm (inset). See also Fig. S1.