Fig. 4. Gli1-mediated Cre recombination in GCNs and BGs. (A) Schematic experimental design for the tamoxifen injection time points used in Gli1CreERT2/+:: R26RYFP/+ mice. Pups were orally injected with TAM at P4~7 (left, for B and D) or P19~22 (right, for C, E), and sacrificed at P25 to analyze the YFP-expressing cells. (B~E) Tamoxifen injection at different time point led to YFP labeled cells that were cerebellar cell-type and specifically regulated Cre-mediated recombination in P25 Gli1CreERT2/+:: R26RYFP/+ cerebellum. Similar to P9 cerebellum, injection of TAM at P4~7 allowed YFP expression which was induced in NeuN+ GCNs (Fig. B~B”), GFAP+ BGs (D~D”), but not in PCP2+ PCs (D), whereas late administration of TAM at P19~22 led to detection of YFP signal in GFAP+ BGs (E~E”), but not in any of GCNs (C~C”) and PCs (E) in P25 Gli1CreERT2/+:: R26RYFP/+ cerebellum. Boxed region in C~E denotes enlarged area in C’~E”. Scale bars=50 μm in B~E, 20 μm in B’~E”. (F~G) Colocalization of YFP+ cells were assessed with confocal images from 4~6 from sagittal sections of 2~3 animals per group as mentioned in the Methods. The specificity and coverage of YFP expression in NeuN+ GCNs and in S100β+ are shown means±SEM.
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