In addition, there was an infection-induced increase in the distance EdU+ cells had traveled along the crypt–villus axis normalized to crypt/villus length (Artis and Grencis, 2008; McDermott et al., 2005) in WT but not Gpr44−/− mice, suggesting that IECs in WT infected mice had an increased rate of movement through the epithelial escalator than in Gpr44−/− mice (Fig. 7, a and c). The gene discussed is PTGDR2; the disease is infection.