PKD1 and cyst: Pkd1–/–;Kcnn4–/– metanephroi (Figure 3B) exhibited ~40% lower cyst area (Figure 3C) and ~30% lower cyst number (Figure 3D) than in Pkd1–/–;Kcnn4+/+ metanephroi, suggesting that KCa3.1 expression contributes not only to cyst enlargement but perhaps also to cystogenesis.