Fig. 1

Ivermectin-induced silencing of Ela1-Cre^ER in the pancreas. Representative immunofluorescent images of postnatal day 21 pancreata. Sections are labeled with antibodies against amylase (red) for acinar cells and YFP (green) for expression of the Rosa26^lsl-YFP reporter of Cre activity. Colabeled with DAPI (blue, faint) for nuclei. Genotype and treatment group are indicated above images. No groups were administered tamoxifen at any time. Column 1 shows no YFP expression in untreated mice lacking the Ela1-Cre^ER transgene (3/3 mice analyzed). Column 2 shows constitutive Ela1-Cre^ER activity in untreated mice (7/7 double transgenic mice analyzed). Column 3 shows constitutive Ela1-Cre^ER activity in spite of ivermectin treatment (2/6 double trangenic mice analyzed) whereas column 4 shows lost constitutive Ela1-Cre^ER activity following ivermectin treatment (4/6 double transgenic mice analyzed)