FIGURE 13.

Kinetics of Ascl1-CreER^T2 and Neurog1-CreER^T2 activity. Both Ascl1-CreER^T2 and Neurog1-CreER^T2 mice retain some NeuroD1 (+)/TdT (+) GBCs at 1-day post-tamoxifen (TAM) administration. (a, b) Immunohistochemistry of TdTomato, NeuroD1, and Tuj1 in Ascl1-CreER^T2 and Neurog1-CreER^T2 driver mice, respectively, at various time points after last tamoxifen administration. (c) Quantification of TdTomato (+) and NeuroD1 (+) double positive GBCs shown above. Counts are from three animals, pooled together to control for tamoxifen labeling efficiency, obtained evenly from across the anterior–posterior axis. Arrowheads indicate triple-labeled cells; at this level of staining sensitivity, Tuj1 will label dividing, NeuroD1 (+) GBCs (Packard et al., 2011a). Scale bar in (b) represents 10 μm and applies to (a) as well substantial proportion of the cells that have undergone recombination using the Neurog1-driver remain as GBCs for more than a day after.