Dynamics of planar cell polarity protein Vangl2 in the mouse oviduct epithelium

Abstract

The planar cell polarity (PCP) pathway regulates morphogenesis in various organs. The polarized localization is a key feature of core PCP factors for orchestrating cell polarity in an epithelial sheet. Several studies using Drosophila melanogaster have investigated the mechanism of the polarized localization. However, to what extent these mechanisms are conserved and how the polarization of core PCP factors is maintained in mature vertebrates are still open questions. Here, we addressed these questions by analyzing the dynamics of Vangl2, a member of core PCP factors, in the mouse oviduct epithelium. Multiple core PCP factors including Vangl2 were expressed in the mouse oviduct in postnatal stages. Vangl1, Vangl2 and Frizzled6 had polarized localization in the oviduct epithelium. Exogenously introduced expression of green fluorescent protein (GFP)-tagged core PCP factors by electroporation revealed that Vangl1, Vangl2 and Prickle2 are localized on the ovarian side of the cell periphery in the oviduct. To visualize the Vangl2 dynamics, we generated the R26-Vangl2-EGFP transgenic mice. In these mice, Vangl2-EGFP was ubiquitously expressed and showed polarized localization in multiple organs including the oviduct, the trachea, the lateral ventricle and the uterus. Fluorescence recovery after photobleaching (FRAP) analysis in the mature oviduct revealed that Vangl2 in the enriched subdomain of cell periphery (cellular edge) was more stable than Vangl2 in the less-enriched cellular edge. Furthermore, when a subregion of a Vangl2-enriched cellular edge was bleached, the Vangl2-enriched subregion neighboring the bleached region in the same cellular edge tended to decrease more intensities than the neighboring sub-region in the next Vangl2-enriched cellular edge. Finally, the polarization of Vangl2 was observed in nocodazole treated mouse viduct, suggesting the maintenance of Vangl2 asymmetry is independent of microtubule formation. Taken together, we revealed the characteristics of Vangl2 dynamics in the oviduct epithelium, and found that Vangl2 forms stable complex at the enriched cellular edge and forms compartments. Our data collectively suggest that the mechanism for maintenance of Vangl2 asymmetry in mature mouse oviduct is different from the microtubule dependent polarized transport model, which has been proposed for the reinforcement of the asymmetry of two core PCP proteins, Flamingo and Dishevelled, in the developing fly.

Planar cell polarity in development and disease

“…Interestingly, while polarized microtubules are essential for establishing some PCP asymmetries, they may be dispensable for maintaining these patterns once they have been stably generated 37,40 , and this supports the notion that the key role of microtubules in PCP patterning is to introduce an initial directional bias. It has separately been shown that intact PCP patterns are necessary for the polarization of microtubule arrays 24,38,41 , demonstrating that intricate and mutual relationships exist between microtubule polarity and planar polarity patterning.…”

“…Directional beating of MCCs has been studied on the amphibian epidermis for nearly 200 years 86 , and not surprisingly, the first description of a role for PCP genes in these cells was in this context 63,87 . PCP signalling is now known to control polarized beating in all MCCs examined to date, including in the mammalian brain 64,88–90 , airway 24 , and oviduct 40,91 . Core PCP localization examined in these tissues reflects that seen in the fly wing; PK and VANGL occupy a domain complementary to that of DVL and FZ (Fig.…”

“…Unlike other epithelia, cells undergoing convergent extension constantly exchange their neighbors. Dynamic analyses of epithelial PCP protein localization with time-lapse imaging and probing localization stability utilizing photobleaching and photoconversion techniques are now providing deeper mechanistic insights into PCP signalling 11,21,40,41 ; studies of PCP involvement in convergent extension should also benefit from the application of similar techniques.…”

Planar Organization of Multiciliated Ependymal (E1) Cells in the Brain Ventricular Epithelium

“…Celsr1, Vangl2, and Fzd3 are similarly accumulated asymmetrically in the apical compartment of RGCs and E1 cells, next to the intercellular junctions (Fig. 1)[13, 15, 56, 58, 71]. Ablation of Vangl2 or Fzd3 affects the establishments of both rotational and translational polarity in E1 cells [13, 14, 56].…”

Centriole positioning in epithelial cells and its intimate relationship with planar cell polarity

“…Over the last decade growing evidence has linked the planar cell polarity (PCP) pathway as a signaling system to regulate polarized ciliary localizations. PCP has been shown to be critical for proper positioning and orientation of cilia in multiciliated cells in the Xenopus larval skin [37–39], ependymal cells in mice [40], and epithelial cells in the oviduct [41, 42]. Similarly, primary cilia positioning is regulated by PCP in the mouse node [43], the outer hair cells in the mouse cochlea [30, 31], the floor plate from zebrafish [22], cell lens in mice [44], and planaria [45].…”