High-time resolution analyses of mitotic compartment responses to local laser cuts. (A–C″) Single confocal section imaging of the PIP₂ probe following local laser ablations, and quantifications of responses. Compartment pseudocleavage furrows overlaid before (purple) and after (green) ablation. Asterisks show cut sites. (A) Minimal response to cutting the center of a metaphase 11 compartment. (A′) Quantifications of minimal compartment area change 1 s after laser cuts of centers of metaphase 11 compartments. Neither the cut compartments nor adjacent compartments changed the area substantially, and the responses of the cut compartments were not significantly different from those of the adjacent compartments. Three interconnected dots of one cut compartment and two adjacent compartments are shown for each of the 10 embryos. (A″) Quantifications of minimal compartment area changes from 1 to 9 s after laser cuts of centers of metaphase 11 compartments. The compartments assessed in A′ were quantified second-by-second until 9 s after ablation. Neither the cut compartments nor adjacent compartments changed area substantially. (B) Green arrows show the increased area of a telophase 11 compartment from 1 to 9 s following a laser cut of its center. Note that adjacent compartments translocate without apparent area change. (B′) Quantifications 1 s after laser cutting show that telophase 11 compartments cut at their center significantly increase in area compared to adjacent compartments with minimal change. Three interconnected dots of one cut compartment and two adjacent compartments are shown for each of the 10 embryos. (B″) Quantifications of compartment area changes from 1 to 9 s after laser cuts of centers of telophase 11 compartments. The compartments assessed in B′ were quantified second-by-second until 9 s after ablation. Cut compartments continued to increase in area from 1 to 9 s, whereas adjacent compartments showed relatively low area changes. (C) Green arrows show increased area of a telophase 11 compartment from 1 to 9 s following a laser cut of one of its nascent caps. Note that adjacent compartments translocate without apparent area change. (C′) Quantifications 1 s after laser cutting show that telophase 11 compartments cut at a nascent cap significantly increase in area compared to adjacent compartments with minimal change. Three interconnected dots of one cut compartment and two adjacent compartments are shown for each of the 10 embryos. (C″) Quantifications of compartment area changes from 1 to 9 s after laser cuts of nascent caps of telophase 11 compartments. The compartments assessed in C′ were quantified second-by-second until 9 s after ablation. Cut compartments continued to increase in area from 1 to 9 s, whereas adjacent compartments showed relatively low area changes.