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. 2021 Sep 7;19(9):e3001376. doi: 10.1371/journal.pbio.3001376

Fig 6. Cdc42 promotes cortical attraction forces through F-actin polarization.

Fig 6

(A) Simplified diagram of the Ran/Cdc42 signaling, emanating from the chromosomes, and leading to the cortical accumulation of F-actin through the activation of the Cdc42, N-WASP, and Arp2/3 pathway. (B) Live imaging of activated oocytes injected with the H2B-mCherry DNA marker alone (control) or in combination with Cdc42T17N (S10 Movie). The Cdc42T17N-injected oocytes presented 2 characteristic phenotypes: a first group extruding a small PB2 (light blue sPB), as compared to controls, and a second group whose spindle relocated toward the center of the cell (dark blue Reloc). (C) Box plots showing the distribution of the distance from the oocyte centroid to the DNA cluster midpoint 90 min after activation. Measurements were performed on 67 control, 27 Cdc42T17N, and 14 Cdc42T17N + Y-2762–treated oocytes, gathered, respectively, from 9, 3, and 4 independent experiments. (D) Box plots showing the distribution of the distance from the oocyte centroid to the DNA cluster midpoint 90 min after activation. Measurements were performed on 55 control, 34 CK-666–treated, and 34 CK-666 + Y-27632–treated oocytes, gathered, respectively, from 8, 3, and 2 independent experiments. Images (right panel): selected examples showing the localization of DNA clusters in fixed oocytes from the different experimental conditions. (E) Live imaging of Y-27632–treated oocytes (activated), injected with the H2B-mCherry DNA marker alone (control) or in combination with Cdc42T17N (S11 Movie). (F) PIV vector fields showing the averaged cytoplasmic streaming pattern in 32 control, 29 Cdc42T17N, 12 Y-27632–treated, and 14 Cdc42T17N + Y-27632–treated oocytes, gathered, respectively, from 8, 3, 3, and 4 independent experiments. Parameters for box plots in C and D are as described in Fig 2. p-values in C and D were obtained using a two-sided Mann–Whitney test. Data underlying this figure can be found in S1 Data. Scale bars = 10 μm. F-actin, actin filament; PB2, second polar body; PIV, particle image velocimetry; sPB, small polar body.