Figure 7. Cell-extrinsic regulation of cytokinesis in EMS depends on direct contact with its neighbor cell, P2.

(A) Schematic of the experimental protocol for the isolation of paired-blastomere doublets. Blastomeres are maintained at the permissive temperature (16°C) during preparation of cell doublets (steps 1 and 2) to ensure the first two-cell divisions occur normally. (B) Representative images showing the cytokinetic outcome of paired blastomeres from control and formin^cyk-1(ts) embryos. (C) Graph showing the frequency of successful cytokinesis for paired blastomeres isolated from control and formin^cyk-1(ts) embryos. (D) Schematic showing the measurement of cell-cell contact diameter to calculate the cell-cell contact area between cells in EMS-P2 doublets (E). Graphs showing the calculated cell-contact area between EMS and P2 cells in paired doublets isolated from control and formin^cyk-1(ts) embryos. Mean ± SD; two-tailed Mann-Whitney test (Supplementary file 1); n.s., no significance, p>0.05; *p≤0.05; **p≤0.01; ***p≤0.001; ****p≤0.0001. Temperature, 26°C; scale bar = 10 µm.