FIGURE 2.

Cre activity of Nefl^CreER/+ mice. Nefl^CreER/CreER mice were crossed with a reporter strain, Ai9, to obtain heterozygous Nefl^CreER/+;Ai9^+/– mice, which were treated with tamoxifen or vehicle on postnatal day 1 (P1) for 4–5 consecutive days. The pups were euthanized on P10 (A), P14 (B), P21 (C), and P28 (D). In the vehicle group, no significant Ai9 tdTomato fluorescence was observed in the cochlear overview or spiral ganglion neuron (SGN) area highlight. However, robust Ai9 tdTomato fluorescence was identified in the cochlear overview and SGN area highlight in heterozygote mice treated with tamoxifen. In the SGN area, Ai9 tdTomato fluorescence was co-labeled with Nefl immunofluorescence in the tamoxifen groups, whereas only Nefl immunofluorescence was observed in the vehicle groups (A–D), suggesting tamoxifen-induced Cre activity of Nefl^CreER/+;Ai9^+/– mouse SGNs. Scale, 50 μm in cochlear overview and 20 μm in SGN highlight.