Fig. 5. Ruffle kymographs monitoring the establishment of contractile polarity over time. The position of cortical ruffles along the anterior (ANT)-posterior (POST) axis is projected onto a calculated ellipse. One half of the ellipse was straightened to generate the x-axis (see Materials and methods). (A) In control embryos, the cortex contracts uniformly after the completion of meiosis. During anteroposterior polarity establishment, the posterior cortex becomes cleared from contractions, whereas the anterior cortex continuous to ruffle. (B) Cdc-42(RNAi) did not prevent the establishment of the contractile polarity. Ruffles were deeper and persisted longer than in control embryos. (C-E) Rho-1(RNAi) (C), cdc-42(RNAi);rho-1(RNAi) (D) and ect-2(RNAi) (E) abolished contractile polarity establishment.