A platform for generating expandable, branching and gene-editable ureteric bud organoid from primary mouse and human ureteric bud progenitor cells and human pluripotent stem cells, and its maturation into collecting duct organoid. Overall design: mRNA profiles of mouse ureteric bud (UB) organoids cultured in mUBCM for 5 days, 10 days and 20 days, as well as mouse collecting duct (CD) organoids and adult mouse CD cells purified by FACS from kidneys of 2-month-old Hoxb7-Venus mice.