Nelson T, et al. - A recent report suggesting the necessity of the transcription factor Early B cell factor 1 (EBF1) for the last stages of metanephric development, and impaired maturation of peripheral glomeruli in mice globally deficient in EBF1 led researchers to investigate the cell type that is driving the glomerular developmental defects in the global EBF1 knockout mice. For this purpose, they deleted EBF1 from the mesangium/pericytes or podocytes in mice. Findings are indicative of a role of EBF1 as a regulator of metanephric development at the last stages of glomerular maturation. The mechanism underlying this effect is the actions of EBF1 in the stromal progenitor (Foxd1⁺) lineage where proper regulation of calcineurin/NFAT signaling and COX-2 expression are mediated by it.