Myosin is up-regulated in ani-1; par-4 and ani-1; pig-1 embryos. (A and B) Myosin accumulation at the anterior cortex after anaphase onset is stronger and lasts longer in ani-1(RNAi); par-4(it47) (A) and ani-1(RNAi); pig-1(gm344) (B) embryos. Intensity of NMY-2::GFP fluorescence was measured during anaphase and cytokinesis at the anterior cortex of embryos of the indicated genotypes (all strains also express an NMY-2::GFP and mCherry::His-58 transgene) and is expressed relative to the intensity measured at anaphase onset. Arrows indicate the mean time of ingression initiation in the different strains. For examples of embryos used for quantifications, see Video 7. Error bars are SEM. (C) Western blots show that total myosin heavy and light chain levels are not affected in ani-1(RNAi); pig-1(gm344) embryos. Tubulin is used as a loading control. (D) At anaphase, P-MLC is not detected at the cortex of most (31/35) control embryos. It accumulates at the equatorial cortex in ani-1(RNAi) (24/32) and pig-1(gm344) (11/19) embryos and spreads along a broader cortical region in ani-1(RNAi); pig-1(gm344) (32/37) embryos. Asterisks indicate DNA. Bars, 10 µm.