Fig. 1

HH-GLI2 signaling maintains GCP in an undifferentiated state and promotes their survival. a Schematic representation of the MASTR approach. The R26^MASTR allele expresses a GFPcre fusion upon Flp induced deletion of a neo (STOP) cassette. When the R26^MASTR allele and the Atoh1-FlpoER transgene are combined with a floxed gene such as Gli2, recombination of the loxP sites occurs in > 98% of GFP+ cells within 3 days of administrating tamoxifen (Tm) at P2. The mutant cells and their progeny can subsequently be identified by the continuous expression of eGFP from the R26 allele. b-c Fluorescent Immuno-Histo-Chemical (FIHC) detection of the indicated proteins and dapi on mid-sagittal sections (lobule VII and VIII) of P8 control R26^MASTR/+; Atoh1-FlpoER/+; Gli2^lox/+ (Atoh1-M-Gli2 het, b) and R26^MASTR/+; Atoh1-FlpoER/+; Gli2^lox/lox (Atoh1-M-Gli2 CKO, c) mice treated Tm at P2. d-f Graphs of the proportion of GFP+ cells in the outer (o) EGL at P8 (n = 3) (d), the proliferation index at P8 (% [GFP+ EdU+] cells of all [GFP+] cells in the oEGL) (n = 3) (e) and the number TUNEL+ particles per section at P4 (n = 3) (f) in Atoh1-M-Gli2 het (control, black) and R26^MASTR/+; Atoh1-FlpoER/+; Gli2^lox/lox (Atoh1-M-Gli2 CKO, red) mice treated with Tm at P2. All of the analyses were performed on 3 midline sections per brain. All graphical data are presented as means ± SEM and significance determined using two-tailed T-test. g-h In situ hybridization of Gli1 mRNA on P0 mid-sagittal cerebellar sections of Gli2^lox/lox (control, g) and Atoh1-Cre/+; Gli2^lox/lox (Atoh1-Gli2 CKO, h) mice. Black arrowhead indicates the loss of Gli1 expression in the anterior mutant EGL, black arrow Gli1 remaining in the posterior EGL and yellow arrowheads indicate Gli1 expression in Bergmann glia in the Purkinje Cell Layer (PCL). i-j FIHC detection of the indicated proteins and dapi on P0 mid-sagittal cerebellar sections of Gli2^lox/lox (control, i) and Atoh1-Cre/+; Gli2^lox/lox (Atoh1-Gli2 CKO, j) mice. High power images are shown of the areas indicated by white rectangles and the thickness of the EGL is indicated by yellow bracket. Scale bars represent 100 μm (b-c) and 500 μm (g-j)