Extended Data Figure 10. Actomyosin flows in wild-type and ani, moe, E-cad and dia mutant conditions.

a–d, Wild-type (a, b; n = 25 cells, 4 pupae) or ani^RNAi (c, d; n = 46 cells, 8 pupae) dividing and neighbouring cells expressing Lifeact–Ruby in a MyoII–3 × GFP tissue. Kymographs in b and d along the yellow boxes in a and c, respectively. Insets and respective kymograph in (a, b) highlight progressive accumulation of MyoII–3 × GFP and Lifeact–Ruby in the neighbours cells, via actomyosin flows, while in (c, d) it denotes a reduction in the actomyosin flows observed in cells neighbouring an ani^RNAi dividing cell, as well as the diminished accumulation of MyoII–3 × GFP and Lifeact–Ruby at the base of the ingressing AJ (see Fig. 1d, e, Supplementary Video 2b and Fig. 4k, l). Note that in c and d, all cells express ani^RNAi cells, marked by Lifeact–Ruby. To visualize F-actin dynamics exclusively in the neighbours in a–d, we photobleached the dividing cell before contractile ring constriction. e–h, Lifeact–Ruby-expressing wild-type (e, f; n = 27 cells, 5 pupae) or moe^RNAi (g, h; n = 30 cells, 10 pupae) cells neighbouring a wild-type dividing cell in a MyoII–3 × GFP tissue. Kymographs in f and h along the yellow boxes in e and g, respectively. Insets and kymographs highlight the progressive accumulation of MyoII–3 × GFP and Lifeact–Ruby in both the wild-type and moe^RNAi neighbours, via actomyosin flows. Dots denote moe^RNAi cells, marked by Lifeact–Ruby. In agreement with our observation that MyoII accumulation occurs in moe^RNAi neighbouring cells (Extended Data Fig. 3h and Supplementary Videos 4c, d), the F-actin flows are similar in velocity and amount to those observed in wild-type neighbouring cells (see m, n). i–l, E-cad (i, j, n = 16 cells, 5 pupae) or dia (k, l, n = 19 cells, 3 pupae) cells, marked by Lifeact–GFP, neighbouring a wild-type dividing cell in a MyoII–3 × mKate2 tissue. Dots denote E-cad (i) or dia (k) mutant cells. Kymographs in j and l generated along the yellow boxes in i and k, respectively. E-cad neighbours accumulate actomyosin at the base of the ingressing AJ (see Fig. 3j) and exhibit actomyosin flows similar to wild-type neighbours (see m and n). By contrast, dia neighbours exhibit delayed accumulation of MyoII (Extended Data Fig. 7i, j). Accordingly, in this context the F-actin flows are slower than in wild-type neighbours (see Fig. 4o, p). m, Percentage of wild-type, moe^RNAi and E-cad neighbouring cells (12, 10, 5 pupae, respectively) exhibiting no flows, intermittent flows (< 3 detectable speckles), or sustained flows (≥ 3 detectable speckles) when facing wild-type dividing cells. n, Actin flow velocity for wild-type, moe^RNAi and E-cad neighbours facing wild-type dividing cells. n/n indicates number of speckles/number of cells (12, 9 and 5 pupae, respectively). Kruskal–Wallis test. Scale bars, 5 μm.