Quantitative differences in Toll-8 expression lead to mutually dependent Toll-8 and Cirl polarity
(A) Stills from a time-lapse movie showing live dynamics of Toll-8-YFP and MRLC-Ch in a nascent Toll-8-YFP-overexpressing clone in a wing disc. Toll-8-YFP becomes detectable at 0 min and increases its levels during the time-lapse. Yellow arrows mark junctions displaying Toll-8 planar polarized enrichment associated with Myo-II enrichment. Cyan arrow indicates an interface between high and low Toll-8 cells. (A′) Zoomed view of a cell (asterisk) that dynamically upregulates expression of Toll-8-YFP during ~50 min. Myo-II is being enriched at junctions that show Toll-8 planar polarity (arrow) and this enrichment is lost once Toll-8 expression reaches similar levels between contacting cells (arrowhead).
(B) Nascent Toll-8-YFP clones in a Cirl-RFP wing disc. Cirl levels are increased at Toll-8-enriched junctions (arrows).
(C) Toll-8 planar polarity versus Cirl planar polarity in trans for the condition shown in (B) show a significant positive correlation. Error band indicates the 95% confidence interval.
(D) Toll-8 planar polarity in nascent Toll-8-YFP clones in control (top, n = 26) or cirl-null mutant (bottom, n = 29) wing discs. Zoomed views on the right. Toll-8 planar polarity is reduced in the absence of Cirl.
(E) Quantifications of Toll-8 planar polarity in cells with low Toll-8-YFP levels in direct contact with cells with high Toll-8-YFP levels for the conditions shown in (D).