Fig. 1

Cilk1 expression in developing molars and developmental anomalies in Cilk1^−/− mice. a–d Cilk1 expression (small brown dots) in frontal sections of the developing first molar (M1) of wild-type mice at E13, E14, E15.5, and E16.5. Cilk1 is weakly expressed in dental epithelium and dental mesenchyme. e–l Tooth germs dissected from maxilla (Mx) and mandible (Mn) of wild-type (WT) and Cilk1^−/− mice at E14.5 and E16.5. Diastemal supernumerary tooth (R2) is observed in Cilk1^−/− mice at E14.5 (f, h). M1 and second molar (M2) are observed in wild-type mice at E16.5 (i, k), while R2 and M1 are observed in Cilk1^−/− mice (j, l). R2 is similar or smaller in size than M1 in both maxilla and mandible of Cilk1^−/− mice at E16.5. m Wild-type mice show the fused palate at E18.5. n Cilk1^−/− mice show cleft palate (asterisk) at E18.5 with two palatal shelves (PS). o–t Cilk1^−/− embryo shows multiple lobules (black arrowheads) in the tongue at E12.5. Scale bars, a–d: 50 μm, e–l: 0.25 mm, m–t: 1 mm