Two types of transgenic constructs were used to make these mice. Construct 1 is the kidney specific (Ksp)-cadherin/β-globin promoter driving the transcription factor tetracycline transactivator (tTAoff) only in renal tubular epithelial cells. Construct 2 possesses a modified cytomegalovirus promoter that, in the presence of tTAoff, produces the tdTomato fluorescent protein and a short hairpin RNA (shRNA) designed to silence angiotensin converting enzyme (ACE) mRNA. Renal confocal microscopy shows a glomerulus (negative) surrounded by tdTomato-positive tubules (orange). Green color is normal tubular autofluorescence. Oral administration of doxycycline (200 μg/ml in the drinking water) inactivates the tTAoff transcription factor, prevents shRNA production, and restores ACE expression. IRES, internal ribosome entry site.