Inactivation of Smad7 leads to compromised cell proliferation in the
developing molar. (A–C) Immunofluorescent staining of Ki-67 on sections
of control and Smad7−/− molar germs at E13.5 (A), E14.5
(B), and E15.5 (C). (A′–C′) Quantification of Ki-67–positive cells in the
dental epithelium and mesenchyme of control and Smad7−/−
tooth germs at E13.5 (A′), E14.5 (B′), and E15.5 (C′). (A′′–C′′) Growth
curves of control and Smad7−/− tooth germ cells plotted
from CCK8 assays at E13.5 (A′′), E14.5 (B′′), and E15.5 (C′′). Statistical analysis
was performed using Student’s t test. *P < 0.05.
**P < 0.01. Scale bars: 100 µm.