Figure 2. Upregulation of Hh target gene expression with concomitant Gli1 protein reduction in the absence of Sufu.

(A–B) β-galactosidase staining of wild-type (wt) and Sufu-deficient (Sufu^f/−; Dermo1^Cre/+; Ptch1^LacZ/+) lungs to detect Ptch1 expression in lung mesenchyme. Ptch1-LacZ expression was stronger and broader in Sufu mutants compared to wt. (C) Western blot analysis of endogenous Gli1 protein levels in wt and Sufu mutant lungs. Gli1 protein levels were decreased in Sufu mutant lungs collected at various stages of lung development. This resembles reduced protein levels of Gli2/3 in Sufu mutant lungs. Likewise, a reduction in Gli1 protein levels was also detected in Sufu-deficient hearts. (D) qPCR analysis of Ptch1 and Gli1 mRNA in wt and Sufu mutant lungs. Ptch1 and Hhip mRNA levels were elevated in Sufu mutant lungs while Gli1 mRNA levels were unaltered. This suggests that reduced Gli1 protein levels in Sufu-deficient lungs are a result of loss of Sufu and not due to changes in Gli1 transcript levels. All values are means ± standard deviation. * P < 0.05; ** P < 0.01; NS, not significant (unpaired Student’s t-test) (n=6 for 12.5 dpc lungs; n=4 for 16.5 dpc lungs; n=4 for 16.5 dpc heart). Elevation of Hhip mRNA levels at 16.5 dpc was not statistically significant likely due to large variations in transcript levels among different samples. Note that Sufu^f/−; Dermo1^Cre/+ lungs/heart are abbreviated as Sufu^−/− lungs/heart while Sufu^−/− embryos represent Sufu null embryos in this figure. FL, full-length; R, repressor. Scale bar = 100 μm for A–B.