Differential expression of Bmp2,Bmp4 and Bmp3 in embryonic development of mouse anterior and posterior palate

Background The palate is differently regulated and deve loped along the anterior-posterior axis. The Bmp signal pathway plays a crucia l role in palatogenesis. Conditioned-inactivation of Bmp type I receptor Alk2 or Alk3 in the neural crest or craniofacial region leads to palatal cleft in mic e. However, how different Bmp members are involved in palatogenesis remains to be elucidated. In the present study, mRNA expression patterns of Bmp2, Bmp3 and Bmp4 in the dev eloping anterior and posterior palates were examined and compared, focusing on t he fusion stage. Methods To detect the expression of Bmp mRNA, antisense rib oprobes were synthesized by in vitro transcription. Radioactive in situ hybridization was performed on sagital and coronal sections of mice head from E 13 to E18. Results The expression of these Bmps were developmentally r egulated in the anterior and posterior palates prior to, during and after palata l fusion. During palatal fusion, Bmp4 expression shifted fr om the anterior to the posterior palate, Bmp2 was highly exp ressed in both the anterior and posterior palates in this process, whereas Bmp3 was only localized in the posterior palate. They showed gen erally non-overlapping pattern in their expression domains. Thereafter, their expression was detected in both the anterior and posterior palates regulating os teogenesis and myogenesis respectively. Conclusions Bmp signalling is involved in palatogenesis in multiple stages and has multiple roles in regulating anterior and posterior pala tal development. Disturbances of Bmp signalling during palatogenesis might be a possible mechanism of cleft palate.