Figure 5.

Yap/Taz regulate transcription of genes necessary for elevation and mineralization in the palatal shelves. (A) Heatmap of the 22 differentially expressed genes (false discovery rate <0.05) in nonelevated posterior palatal shelves in Yap^fl/fl;Taz^fl/fl control and Yap^fl/fl;Taz^fl/fl;Col2^Cre mutant embryos at E14.5. Highlighted with arrows are the 3 most differentially expressed genes, Ibsp, Phex, and Loxl4. (B–G′′) Messenger RNA levels of Ibsp (B–C′), Phex (D–E′), and Loxl4 (F–G′) in the posterior palatal shelves in Yap^fl/fl;Taz^fl/fl control (B, D, F) and Yap^fl/fl;Taz^fl/fl;Col2^Cre mutant (C, E, G) embryos at E14.5. Ibsp was expressed in the mineralizing mandible (B, C) and posterior palatal shelf mesenchyme in the ossification region, where it was decreased in the mutant compared to control (B′, C′, yellow dashed circle). Phex and Loxl4 were similarly expressed in the ossification center in the posterior palatal mesenchyme and decreased in Yap^fl/fl;Taz^fl/fl;Col2^Cre mutant embryos compared to control (D′, E′, F′, G′, yellow dashed circle). Loxl4 was also expressed in Meckel’s as well as cranial base cartilages, where Col2^Cre drives recombination, and there was a decrease in Loxl4 expression in these cartilages in the Yap^fl/fl;Taz^fl/fl;Col2^Cre embryos compared to control (F, G, white arrowheads). Scale bar = 1 mm. (H–K) Masson trichrome staining (blue) in the posterior palatal shelf shows decreased staining in the ossification region of the Yap^fl/fl;Taz^fl/fl;Col2^Cre mutant embryo compared to Yap^fl/fl;Taz^fl/fl control at E14.5 (H, H′, I, I′), and staining was similar in control and mutant at E15.5 (J, K). Scale bar = 200 µm.