Flamingo, a seven-pass transmembrane cadherin, regulates planar cell polarity under the control of frizzled

We identified a seven-pass transmembrane receptor of the cadherin superfami ly, designated Flamingo (Fmi), localized at cell-cell boundaries in the Dro sophila wing. In the absence of Fmi, planar polarity was distorted. Before morphological polarization of wing cells along the proximal-distal (P-D) ax is, Fmi was redistributed predominantly to proximal and distal cell edges. This biased localization of Fmi appears to be driven by an imbalance of the activity of Frizzled (Fz) across the proximal/distal cell boundary. These results, together with phenotypes caused by ectopic expression of fz and fm i, suggest that cells acquire the P-D polarity by way of the Fz-dependent b oundary localization of Fmi.