FIGURE 3.

Characterization of EAAT2-flox mice crossed with Cre lines (RIP-Cre and IPF1-Cre) causing pancreas-selective excision. A, PCR of genomic DNA of the pancreas from homozygote (f/f) EAAT2-flox without (cre−) or with (cre+) either RIP-Cre or IPF1-Cre as indicated. Note that the fKO allele becomes detectable when Cre is present. This shows that the recombination indeed takes place. B, confocal microscopy images of pancreas sections from WT (EAAT2-flox) or cKO (either EAAT2-flox × RIP-Cre or EAAT2-flox × IPF1-Cre as indicated) labeled with antibodies either to Cre (green; 1:200) or to insulin (green; 1:500) as indicated. Note the multiple Cre-positive nuclei (panels f, j, h, and l). Arrows in f and g point to a few of them. The sections were mounted in a DAPI-containing medium to visualize cell nuclei (blue). Note that insulin was readily detectable in all sections (panels a–d), whereas Cre was only detectable in islet cells in Cre-positive (cKO) mice (panels j and i), attesting to the specificity of the antibodies. Panels e, f, g and h are merged images showing both DAPI and Cre. Panels i and j are merged to give f, and k and l are merged to give h. Also note that EAAT2 was present in the brains of both WT and cKO mice (panels m–p) as indicated. Immunoperoxidase labeling of parasagittal brain sections was carried out with anti-B563 (Ab355; 0.1 μg/ml) antibody to the C terminus of EAAT2. Scale bars, 20 μm (pancreas) and 2 mm (brain). C and D, body weights of EAAT2-flox mice (WT) and cKO mice as indicated. The mice in C were 6–7 weeks old, whereas those in D were 5–6 weeks old (M, male; F, female). E and F, glucose tolerance tests of the male WT and cKO from RIP-Cre (E) and IPF1-Cre (F). Note that WT (EAAT2-flox) and cKO have similar glucose tolerance. G and H, the percentages of insulin-positive cells in the islet were the same in EAAT2-flox mice (WT) and their cKO littermates. Error bars, S.E.