Planar polarization of node cells determines the rotational axis of node cilia

Abstract

Mouse node cilia are posteriorly tilted to generate a leftward fluid flow and left/right asymmetry in the embryo, but how the tilt comes about was not known. The basal bodies of node cilia gradually shift from a central position towards the posterior side of node cells in a dishevelled and non-canonical Wnt signalling-dependent manner and follow a shift in Dvl localization to the posterior. Rotational movement of the node cilia generates a leftward fluid flow in the mouse embryo1 because the cilia are posteriorly tilted2,3. However, it is not known how anterior-posterior information is translated into the posterior tilt of the node cilia. Here, we show that the basal body of node cilia is initially positioned centrally but then gradually shifts toward the posterior side of the node cells. Positioning of the basal body and unidirectional flow were found to be impaired in compound mutant mice lacking Dvl genes. Whereas the basal body was normally positioned in the node cells of Wnt3a−/− embryos, inhibition of Rac1, a component of the noncanonical Wnt signalling pathway, impaired the polarized localization of the basal body in wild-type embryos. Dvl2 and Dvl3 proteins were found to be localized to the apical side of the node cells, and their location was polarized to the posterior side of the cells before the posterior positioning of the basal body. These results suggest that posterior positioning of the basal body, which provides the posterior tilt to node cilia, is determined by planar polarization mediated by noncanonical Wnt signalling.

Cite this article

Hashimoto, M., Shinohara, K., Wang, J. et al. Planar polarization of node cells determines the rotational axis of node cilia. Nat Cell Biol 12, 170–176 (2010). https://doi.org/10.1038/ncb2020

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