RAB-5 controls PAR-6 cortical localization independently of actomyosin contractility.

<p>(<b>A</b>) Midplane images of PAR-6::GFP in <i>control(RNAi)</i> and <i>rab-5(RNAi)</i> embryos at pronuclear meeting, i.e., at the end of the establishment phase of polarity. Quantitation of fluorescence intensity along the circumference of the cortex reveals that the size of PAR-6::GFP cortical domain is more anterior in <i>rab-5(RNAi)</i> embryos compared to <i>control(RNAi)</i> (red star, p = 6.11×10⁻⁰⁶, Student's t-test). (<b>B</b>) Midplane images of GFP::PAR-2 in <i>control(RNAi)</i> and <i>rab-5(RNAi)</i> embryos at pronuclear meeting. Quantitation of fluorescence intensity along the cortex shows that the size of GFP::PAR-2 cortical domain is similar in <i>control(RNAi)</i> and <i>rab-5(RNAi)</i> embryos (p = 0.98, Student's t-test). Quantitation excluded the anterior crescent of GFP::PAR-2 visible in wild-type embryos (arrow) but absent from <i>rab-5(RNAi</i>) embryos. (<b>C</b>) Images of NMY-2::GFP at the mid-plane of <i>control(RNAi)</i> and <i>rab-5(RNAi)</i> embryos at pronuclear meeting. Quantitation of fluorescence intensity along the cortex shows that the size of NMY-2::GFP cortical domain is similar in <i>control(RNAi)</i> and <i>rab-5(RNAi)</i> embryos (p = 0.17, Student's t-test). (<b>D</b>) Images of NMY-2::GFP at the cortex of <i>control(RNAi)</i> and <i>rab-5(RNAi)</i> embryos during the phase of establishment of polarity. Kymographs were generated along the antero-posterior axis (orange lines). The average velocity of NMY-2 puncta is similar in <i>control(RNAi)</i> and <i>rab-5(RNAi)</i> embryos (p = 0.86, Student's t-test). In each frame anterior is to the left and white arrowheads indicate the boundary of cortical fluorescence. n, number of embryos analyzed. Error bars represent standard deviation. Scale bars, 10 µm.