Figure 5.
Gβ13F/Gγ1 Activates and Polarizes Junctional Rho1 Signaling in the Ectoderm
(A) Apical (0 μm) and junctional (1.5 μm) confocal z sections of ventro-lateral ectodermal cells expressing Ani-RBD::GFP in control, Gγ1 germline clone (Gγ1−), and Gβ13F/Gγ1-overexpressing embryos (Gβ13F/Gγ1++).
(B and C) Mean medial-apical and junctional Rho1-GTP intensities in control and Gγ1− embryos. Medial and junctional Rho1-GTP intensities are decreased in Gγ1 mutant compared to control embryos.
(D) Mean junctional intensity of Rho1-GTP according to the angle of the junctions in control and Gβ13F/Gγ1++ embryos.
(E) Rho1-GTP amplitude of polarity.
(F) Medial-apical Rho1-GTP intensities in control and Gβ13F/Gγ1++ embryos.
(G) Confocal acquisitions (4.5 μm projections) showing Myo-II::mCherry in control and Gβ13F/Gγ1++ embryos (yellow arrowheads show two strong compartment boundaries cables of Myo-II in a control embryo; orange arrowheads show the ectopic supracellular cables of Myo-II induced by Gβ13F/Gγ1 overexpression).
(H) Left panel: mean junctional intensity of Myo-II::mCherry according to the angle of the junctions in control and Gβ13F/Gγ1++ embryos. Right panels show the distributions of junctional Myo-II intensity values for transverse (0°–15°) and vertical junctions (75°–90°) in control and Gβ13F/Gγ1++ embryos. We observed a mild statistical difference at the transverse junctions (Kolmogorov-Smirnov two-sample test; p < 0.05). This is explained by an increase in the lower Myo-II intensity values in Gβ13F/Gγ1++ embryos as compared to control. At vertical junctions, a strong statistical difference was observed (p < 10−7) as a consequence of a global increase in Myo-II intensity values in Gβ13F/Gγ1++ embryos compared to control. p values for Kolmogorov-Smirnov test in each comparison are indicated on the plot. ns, not significant, p > 0.05.
(I) Quantification of Myo-II amplitude of polarity in control and Gβ13F/Gγ1++ embryos.
Scale bars represent 5 μm. Means ± SEM are shown. Statistical significance has been calculated using Mann-Whitney U test. ns, p > 0.05; ∗p < 0.05; ∗∗p < 0.01.