A dynamic airway epithelium injury and repair process is observed in both WT and Xb130 KO mice (A). One day after tracheal transplantation, many epithelial cells detached from the basement membrane (D1, * the detached epithelial cells). On Day 3, survived epithelial cells became flat and elongated to cover the basement membrane (D3). From Day 5 to Day 7, epithelium was repopulated with cuboidal shaped cells (D5, D7). The epithelial cells were further differentiated towards pseudo-stratified layer (D10, D14). Severe epithelial hyperplasia was noted in KO mice in comparison with WT mice at Day 10 (A and B). After transplantation, XB130 mRNA levels were reduced at Day 3 and Day 5, and then increased afterwards (C).