Reciprocal Induction
Ureteric Bud>Mesenchyme
Wnt6, Wnt9a,Wnt-11, FGF-2,9,18, TIMP, IL-6 Cytokines, BMP-7.
Mesenchyme>Ureteric Bud
GDNF, FGF-7, pleiotrophin,  BMP-4, HGF, amphiregulin.
Stroma>Ureteric Bud
RA dependent factor, BMP-4, BMP-6.
Ureteric Bud>Stroma
Unknown signal.
Mesenchyme>Stroma
BMP-7.
Stroma>Mesenchyme
Unknown Signal.