RAB-5 Regulates PAR-6 Cortical Dynamics Figure 1. Depletion of RAB-5 and other endocytic regulators results in polarity phenotypes in early C. elegans embryos. (A) Midplane DIC images from time-lapse acquisitions of developing wild-type or par-2(it5ts) embryos undergoing first or second division with the indicated RNAi treatment. All of the embryos depicted successfully completed their first and second cytokineses. In each frame, anterior is to the left and arrowheads indicate centrosome position. Scale bar, 10 mm. (B) Quantitation of posterior spindle displacement in zygotes of each background, as determined by measuring the ratio between the position of anterior vs posterior centrosome. (C) Quantitation of the asynchrony between AB and P1 division at the 2-cell stage, as determined by measuring the time difference between cytokinesis onset in each cell. Stars indicate statistical significance (p,0.05, Student’s t-test) when compared to control(RNAi) in wild type (red stars) or par-2(it5ts) backgrounds (blue stars). Depleting RAB-5 modulates all polarity-related phenotypes that were quantitated. n, number of embryos analyzed. Error bars represent standard deviation. doi:10.1371/journal.pone.0035286.g001 microscopy allows the illumination and detection of fluorophores that are present within 200 nm of the coverslip, revealing events that occur specifically at the cell cortex with high resolution. While PAR-6 distribution appears uniform and continuous when observed in mid-plane imaging sections [17], it was previously reported to localize to puncta when observed in cortical imaging PLoS ONE | www.plosone.org 3 April 2012 | Volume 7 | Issue 4 | e35286