Figure 2.
Myosin II Polarizes with Mechanical Stretch
(A) Wing disc expressing E-cad::GFP and Sqh::mCherry prior to stretch (anchor) and after stretch (15 min). (A′) Insets of discs shown in (A).
(B) Schematics demonstrating change in Sqh concentration before and after stretch on vertical (V) and horizontal (H) junctions.
(C) Quantification of mean fluorescent intensity of E-cad::GFP and Sqh::mCherry on horizontal (H) junctions relative to the intensity on vertical (V) junctions (referred to as “polarity”) prior to and after 15 min stretch. The detailed rationale of intensity determination is described in Figure S2 and in STAR Methods.
(D and E) Quantification of Sqh::mCherry (D) and E-cad::GFP (E) concentration (i.e., mean intensity per junctional unit area) prior and after stretch on both horizontal and vertical junctions normalized to starting concentration on non-stretched (anchored) vertical junctions.
(F) Quantification of total amount of Sqh::mCherry and E-cad::GFP fluorescence on vertical and horizontal junctions in anchored and stretched discs.
(G) Tissue expressing E-cad::GFP and Sqh::mCherry subjected to increasing levels of stretch.
(H) Quantification of Sqh::mCherry polarity (as in C) of experiment described in (G). The level of stretch is measured as a change in tissue strain (deformation relative to unstretched tissue).
(I–K) Sqh::mCherry polarity emergence as a function of cell aspect ratio change (I), stress (J), and stress applied on average cell area of 10 μm2 (K).
Yellow asterisks indicate equivalent regions in the tissue. N = 8 wing discs (A–F). N = 3 wing discs (G–K). All experiments are plotted as mean ± S.E.M.; ∗ p < 0.05, **p < 0.01, ***p < 0.001 with t test. Scale bars, 5 μm (A), 3 μm (A′), and 10 μm (G).