RESEARCH NOTE: Effect of inhibition of bone morphogenetic protein signaling pathway by dorsomorphin on the establishment of embryo polarity

Bone morphogenetic proteins (BMPs) play a crucial and conserved role in establishing embryo polarity across the animal kingdom. However, it is not known how different levels of BMP activity affect embryo polarization in amniote species. To address this question, here we treat dorsomorphin, a selective inhibitor of the BMP signaling, at various concentrations, on early chick embryos and observe the effect on primitive streak formation. In our results, dorsomorphin affects primitive streak formation in a dose-dependent manner, gradually inhibiting streak morphology from the anterior to the posterior direction. Additionally, at higher concentrations, dorsomorphin induces enhanced morphological change in isolated anterior cut-half embryos. Taken together, our results suggest that BMP inhibition by dorsomorphin not only inhibits the formation of the anterior primitive streak but also, at higher concentrations, indirectly inhibits the posterior region, possibly by the ectopic recruitment of cells in the non-posterior areas.