EPCAM and infection: To verify that Shh was indeed deleted in KP;Shhfl/fl mice, we isolated EpCAM+;GFP+ infected lung epithelial cells by FACS from KPmTmG and KPmTmG;Shhfl/fl mice 3 weeks after adeno-cre infection, analogous to Supplementary Fig. 6b, and tested for Shh mRNA expression by qPCR.