Fig. 9
From: Progressive tooth pattern changes in Cilk1-deficient mice depending on Hedgehog signaling
Tooth pattern changes along a gradient of Hedgehog signaling activity. a, b Quantification of each phenotype penetrance in various genotypes. Cilk1–/– mice display 100% penetrance of R2 in both maxilla and mandible. In Cilk1–/–;PCS1–MRCS1△/△ mice, R2 formation and molar fusion are observed in 54.5% and 45.5% of maxilla, respectively, while the mandible exclusively exhibits R2 formation in all cases. While Krt14-Cre;Cilk1fl/fl exhibited a WT-like phenotype with no changes in tooth patterning, Wnt1-Cre;Cilk1fl/fl, PCS1–MRCS1△/△, Cilk1–/–, and Cilk1–/–;PCS1–MRCS1△/△ all displayed patterns of R2 formation. However, a molar fusion phenotype was observed only in the maxilla of Cilk1–/–;PCS1–MRCS1△/△. c, d Graph showing the relative size of M1 to second molar (M1/M2 ratio) in wild-type and Krt14-Cre;Cilk1fl/fl mice and the relative size of R2 to M1 (R2/M1 ratio) in Wnt1-Cre;Cilk1fl/fl, Cilk1–/–, and Cilk1–/–;PCS1–MRCS1△/△ mice at PN 0. The size ratio of R2 relative to M1 increases significantly and progressively from Wnt1-Cre;Cilk1fl/fl mice to Cilk1−/− mice, and further to Cilk1−/−;PCS1–MRCS1△/△ mice. The mandibular R2/M1 ratio in Cilk1–/–;PCS1–MRCS1△/△ mice ranges from 0.90 to 1.16, whereas the maxillary R2/M1 ratio exhibits broader variability, ranging from 0.90 to 2.61. e A hypothetical model for tooth pattern formation influenced by Hh signaling: exploring how R2 and M1 interact. **P < 0.01
