Vertex sliding drives intercalation by radial coupling of adhesion and actomyosin networks during Drosophila germband extension
- University of Denver, United States
Figures
Figure 1 with 1 supplement
Enrichment and dynamics of E-cadherin at vertices.
(A) Vertex enrichment of E-cadherin at the initiation of GBE. Endogenous locus E-cad:GFP (green) and plasma membrane marker (Gap43:mCh, red). Single pixel intensity line plot (right) for both …
Figure 1—figure supplement 1
Method of segmentation and vertex analysis showing that vertices become increasingly enriched with E-cadherin prior to the start of cell intercalation.
(A) Images showing a watershed segmentation sample: a raw image in the Gap43:mCh channel (left), raw image with the watershed segmentation lines overlaid in red (middle), and a black and white image …
Figure 2
Radial coupling and sliding of cell vertices during intercalation.
(A) Schematic showing line tension model, in which tensioned springs pull across interface lengths on either side of a contracting interface. Blue and gray dots indicate tricellular vertices. (B) …
Figure 3 with 1 supplement
Ratcheted vertex movement is coordinated with changes in apical cell area.
(A–A’) Intercalary cell undergoing apical area oscillations colored blue for maxima and red for minima (A) and plot of the area over time (A’). Gray dashed lines indicate image time points. (B) Plot …
Figure 3—figure supplement 1
Instantaneous phase of area oscillations and junction ratcheting.
(A, A’) Cell area (A) and phase (A’) plots showing the same data in Figure 3B and B’ except the raw area trace is shown in blue. (B) Plots of a T1 junction length (green) and cell area (blue) of the …
Figure 4 with 2 supplements
E-cadherin stabilizes cell vertices.
(A) Example of a cell contracting in area while vertical interfaces contract. Top: Gap43:mCh (plasma membrane) channel with cell color-coded such that darker blue represents smaller apical area. …
Figure 4—figure supplement 1
Vertex E-cadherin enrichment is anti-correlated with area oscillations.
(A) E-cad:GFP images at four time points in which enrichment at the vertex (yellow arrowhead) alternates between maxima and minima. (A’) Plot of the vertex intensity ratio for E-cadherin (green) and …
Figure 4—figure supplement 2
Stabilized E-cadherin displays a reduced dynamic range while still possessing oscillations in apical cell area, but junction ratcheting is reduced.
(A) Distribution of intensity ratios for E-cad:GFP (top) and Gap43:mCh (bottom) for wild-type embryos (left column) and chlorpromazine injected embryos (right column). Wild-type distributions are …
Figure 5 with 1 supplement
Cell-specific phase anisotropy drives vertex displacements.
(A) Illustration of cell undergoing anisotropic apical area contraction. Red arrows represent inward contractile force. (A’) Illustration of vertex displacement (red arrow) broken into tangential …
Figure 5—figure supplement 1
Reduced vertex displacements in stabilized E-cadherin embryos.
(A) Heat maps depicting vertex displacement rate (color scale shown on right) against the cell phases of cell A and B (left panel) and cell A and C (right panel) in embryos injected with 10 mM …
Figure 6 with 1 supplement
Myosin II dynamics at vertices correlate with, but slightly precede, E-cadherin.
(A) Live imaging of Myosin II (mCh:Sqh, red) and E-cad:GFP (green) embryos during GBE. (A’) Single pixel intensity line plot between arrowheads shown in (a). (A’’) Quantification of Myosin II …
Figure 6—figure supplement 1
Myosin II localizes to cell vertices with E-cadherin, slightly precedes E-cadherin at the vertices, and is preferentially recruited to vertices associated with AP interfaces.
(A) Embryos expressing endogenously tagged Myosin II heavy chain (Zipper:GFP) and membrane marker Gap43:mCh (left panel). Plot corresponds to the single pixel intensity along the line indicated by …
Figure 7 with 1 supplement
Myosin II function is required for E-cadherin dynamics.
(A,B) E-cad:GFP image of cell and single pixel intensity line plot between arrowheads for 100 mM (A) and 25 mM (B) Y-27632 injection. (C,D) Heat map and plot of the normalized E-cad:GFP intensity at …
Figure 7—figure supplement 1
E-cadherin vertex enrichment is lost in sqhAX mutant embryos and area oscillation amplitude is reduced under Y-27632 treatment.
(A) sqhAX mutant embryos expressing E-cad:GFP and membrane marker Gap43:mCh. sqh encodes the regulatory light chain of Myosin II in Drosophila. Plot corresponds to the single pixel intensity along …
Author Response Image 1
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Videos
Video 1
E-cadherin intensity ratio of vertices are dynamic.
Time-lapse images of an embryo expressing the adhesion marker E-cad:GFP during germband extension. The vertex (marked by yellow arrow) exhibits dynamic changes in E-cadherin enrichment. The …
Video 2
Contracting vertices slide along cell interfaces.
Time-lapse images of an embryo expressing the membrane marker Gap43:mCherry during germband extension. A single vertex can move independently of adjacent vertices and interfaces to result in the …
Video 3
Cell area oscillations during germband extension.
Time-lapse images of a cell (shaded blue) expressing the membrane marker Gap43:mCherry undergoing area oscillations (top) and a plot of the cell area (bottom) over time. Total time is 264 s, 45 …
Video 4
Cell area oscillations in chlorpromazine injected embryo.
Time-lapse images of a cell (shaded blue) expressing the adhesion marker E-cad:GFP undergoing area oscillations (top) and a plot of the cell area (bottom) over time. Total time is 151.8 s, 45 …
Video 5
Myosin II flows toward vertices.
Time-lapse images of an embryo expressing E-cad:GFP and mCherry:Myosin II. Myosin II from the medial/apical region of the cell flows toward a vertex, resulting in Myosin II vertex enrichment. …
Additional files
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Transparent reporting form
- https://doi.org/10.7554/eLife.34586.022
