Dynamics of furrow ingression in ani-1; par-4 embryos. (A and B) During ingression, furrow position does not change in control embryos whereas it is strongly displaced in ani-1(RNAi); par-4(it47) embryos. Furrow position during ingression is monitored with an NMY-2::GFP transgene (green). DNA is monitored with an mCherry::HIS-58 transgene (red and asterisks). Images were acquired at the onset of cytokinesis (A and B), during ingression (A′ and B′), and just after furrow closure (A″ and B″). Arrowheads and white dashed lines indicate the position of initial ingression. Bars, 10 µm. See also Fig. S4 (A and B) and Video 6. (C) Graphs representing the position of the furrow tip during ingression of embryos of the indicated genotypes (all strains also express an NMY-2::GFP and mCherry::HIS-58 transgene). The furrow tip on the embryo side where ingression first initiated was tracked from ingression initiation until furrow closure. Its position is expressed as a percentage of embryo length (0% corresponds to the anterior pole and 100% to the posterior pole). Each colored track corresponds to the furrow tip position of a single embryo. 18/21 ani-1(RNAi); par-4(it47) embryos displayed such a furrow displacement; others are represented in Fig.S4 (A and B).