UBC and Renal cyst: As reported previously (Piontek et al, 2007; Ma et al, 2013), cell proliferation was markedly increased in cystic kidneys and the number of EdU-positive kidney epithelial cells was higher in 21-d-old Ubc-CreERT2;Pkd1f/f mice induced by 4-hydroxytamoxifen (4-OHT), compared with wild-type littermates.