Western blot analyses of Tet-regulated transgene expressing murine hearts. A. Western blot images from mice left uninduced (ON DOX) and induced to express the transgene for one day (OFF DOX 1 day), seven days (OFF DOX 7 days), or twenty-eight days (OFF DOX 28 days), and B. corresponding densiometry analyses of the Western blot bands corresponding to; Notch-1, DLL4, PDGF-β, HA, and GAPDH. Paired t test analyses were conducted on OFF DOX 1 day versus OFF DOX 28 days data. (** denotes p<0.01, and NS denotes “not significant”; n=4 biological replicates for each time point).