PC1 expression was induced with tetracycline (2 μg/ml) for different time points.
A, PC1 was induced at the same time in a set of MDCK cells, and proteins were harvested at different time points (3, 5, 7, and 24 h). This experiment again demonstrated that PC2 down-regulation by PC1 is dose-dependent. B, summary of PC2 expression when PC1 is titrated.