Fig. 4: Increased Hh signaling promotes proliferation and expansion of MG basal cells.

a–f Progressive expansion of acinar basal cell clusters (black arrows) in GLI2ΔN-expressing MG after 2 (a, b), 4 (c, d), and 7 (e, f) days of doxycycline treatment at 8 weeks of age. Meibocytes were reduced by 7 days (f, green arrows). g–l Progressive expansion of GLI2ΔN⁺/KRT5⁺ cells (yellow arrows) and reduction of PLIN2⁺ meibocytes (white arrows) in Gli2ΔN^Krt5rtTA MG acini after 2 (g, h), 4 (i, j) and 7 (k, l) days of doxycycline treatment. N = 3 control mice lacking Krt5-rtTA or tetO-GLI2ΔN (2 males and 1 female) and n = 3 Gli2ΔN^Krt5-rtTA mice (2 males and 1 female) were analyzed at each time point in (a–l); representative samples are shown. m–p Hyperproliferation of GLI2ΔN⁺ cells in Gli2ΔN^Krt5-rtTA MG acini (m, n, yellow arrow) and ducts (o, p, white arrow). q, r Quantification of acinar basal cell (q) and ductal basal cell (r) proliferation. Samples from n = 5 control mice (3 males and 2 females) lacking Krt5-rtTA or tetO-GLI2ΔN and samples from n = 5 Gli2ΔN^Krt5-rtTA mice (3 males and 2 females) were analyzed in (m–r). Statistical significance in (q, r) was calculated with unpaired two-tailed Student’s t-test. Data are presented as mean +/− SEM. At least 100 acinar cells and 110 ductal cells were analyzed from each animal. Source Data for (q, r) are provided as a Source Data file. s, t Overgrowth of Ptch1-deficient acinar basal cells (yellow arrows) in KRT14-Cre^ERT2 Ptch1^fl/fl mice 12 weeks after tamoxifen treatment at 8 weeks of age. u, v Expansion of KRT5⁺ cells in Ptch1-deficient acini (red arrows). Independent biological samples from n = 3 male KRT14-Cre^ERT2 Ptch1^fl/fl mice, n = 2 age-matched male controls and n = 2 age-matched female controls were analyzed in (s–v). Representative images are shown. Scale bars: 50 μm.