FIGURE 1:

The dividing P₄ blastomere undergoes normal furrow ingression. (A) Confocal images (maximum intensity projection of three consecutive Z planes) of a control embryo expressing NMY-2::GFP (green), a membrane marker (TagRFP::PH; magenta), and a germ granule marker (PGL-1::RFP; magenta). The region delineated by the white dashed square is magnified by fourfold in the inset and shows a somatic cell and a P₄ cell upon initiation of cytokinetic furrow ingression. The schematic illustration depicts the region of interest for monitoring furrow progression. (B, C) Time-lapse confocal images of the division plane in a somatic (B) and P₄ (C) cell from a control embryo expressing the markers described in A. Time 0 (seconds) corresponds to the onset of cytokinetic furrow initiation. (D, E) Quantification of cytokinetic furrow diameter (D) and duration of cytokinetic furrow ingression (E) from the onset of furrow initiation to the completion of furrow ingression in wild-type somatic (n = 54; dark gray) and P₄ (n = 27; light gray) cells. ***: p < 0.001. Scale bar for embryo in A, 10 μm; scale bar for insets in B and C, 2 μm.