Metanephrogenic blastema

The metanephrogenic blastema or metanephric blastema (or metanephric mesenchyme, or metanephric mesoderm) is one of the two embryological structures that give rise to the kidney, the other being the ureteric bud.
The metanephric blastema mostly develops into nephrons, but can also form parts of the collecting duct system.
The system of tissue induction between the ureteric bud and the metanephric blastema is a reciprocal control system. GDNF, gonadal derived neurotrophic factor, is produced by the metanephric blastema and is essential in binding to the Ret receptor on the ureteric bud, which bifurcates and coalesces as a result to form the renal pelvis, major and minor calyces and collecting ducts. Mutations in the EYA1 gene, which is a GDNF transcription factor, lead to the renal abnormalities of BOR syndrome (branchio-oto-renal syndrome).