Figure 1. Experimental procedure used to investigate the role of Pax6 in the adult mouse pancreas.

(A) Timeline of the experiment. Mice were bred to obtain the various experimental and control genotypes. After a pre-experimental period of 6 months (indicated by the period to the left of timepoint = 0 weeks) all mice received daily injections, with tamoxifen or oil only, on 5 consecutive days during week 1. Blood glucose level and glucose tolerance measurements were carried out in the week prior to the injections and in the final week (week 5). All mice were sacrificed at the end of week 5 and tissues were fixed for immunohistochemistry (B) Schematic representation of the combinations of genotypes and treatments (oil or tamoxifen injection) of all animals used in the study. Animals were sorted into control (oil only control or Tamoxifen control) or CPTD6 (CreER™-floxed Pax6-Tamoxifen-Diabetic) groups. (C) Graph showing male mouse body weights from 4 weeks pre-treatment until 5 weeks post-treatment, with a time-line of the procedure shown at the top. All animals exhibited healthy body weight prior to treatment. During the 5 day period of daily injections all animals lost some weight, but recovered in the week following the injections. While control animals continued to gain weight and were back to pre-treatment body weight at termination, CPTD6 animals began to lose weight again from the second week post-treatment onwards until termination of the experiment. Data are shown as mean ± SEM (Standard error of the mean). (D) Immunohistochemistry for Pax6 was used to assess the efficiency of the Cre-mediated deletion of Pax6, by staining for the presence or absence of Pax6. Control animals show nuclear Pax6 immuno-reactivity in the pancreatic islet cells. The CPTD6 islets show absence of Pax6 immuno staining in the large majority of cells, indicating successful Cre-mediated inactivation of the Pax6 gene. Scale bar, 50 µm.