Volume 24, Issue 3, Pages 256-270 (February 2013) Interplay between the Dividing Cell and Its Neighbors Regulates Adherens Junction Formation during Cytokinesis in Epithelial Tissue  Sophie Herszterg, Andrea Leibfried, Floris Bosveld, Charlotte Martin, Yohanns Bellaiche  Developmental Cell  Volume 24, Issue 3, Pages 256-270 (February 2013) DOI: 10.1016/j.devcel.2012.11.019 Copyright © 2013 Elsevier Inc. Terms and Conditions

Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions

Figure 1 MyoII, E-Cad, and Membrane Dynamics during Epithelial Cytokinesis (A) Time-lapse images of a MyoII:GFP and H2B:mRFP (not shown) expressing dividing cell (asterisk). Time t = −140 s corresponds to anaphase onset and t = 0 corresponds to cytokinesis onset. Top view apical: confocal section at the level of the apical adhesion belt (left schematics). Open arrowhead: contractile ring formation. Arrows at t = 35 s and t = 105 s: deformation of the dividing cell at the division plane. Arrowheads: detachment of the contractile ring from the apical cortical MyoII:GFP belt. Arrow at t = 385 s: midbody. Bracket: MyoII:GFP enrichment at the daughter cell interface. Front view: section along the apical-basal axis of the cell, at the plane of the contractile ring (left schematics). Arrows: contractile ring and midbody. Arrowheads: detachment of the contractile ring from the apical cortical MyoII:GFP belt. Bracket: MyoII:GFP enrichment at the daughter cell interface. Gray regions on top indicate the panels corresponding to the asymmetric phase and the symmetric phase of cytokinesis, as defined in the main text. MF: midbody formation. See also Movie S1. (B–B″) Schematics of the regions of the contractile ring used to quantify the apical (blue) and basal (red) mean MyoII:GFP intensities (average ± standard deviation (SD), n = 10) (B), ring lengths (average ± SD, n = 10) (B′) and constriction rates (average ± SD, n = 10, see Experimental Procedures) (B″) during the asymmetric phase (light gray) and the symmetric phase (dark gray) of cytokinesis. (C) Apical top view of a dividing cell (asterisk) expressing E-Cad:GFP and PH:ChFP. White arrows: cell deformation at the division plane. White arrowheads: membrane furrow. Yellow arrows: faint E-Cad:GFP signal at the furrow. Open yellow arrowhead: local disruption of the E-Cad:GFP belt at the edges of the furrow. Yellow brackets: space in between the two portions of furrow. Yellow dots: membrane juxtaposition. White bracket: long interface between the daughter cells. Yellow arrowheads: punctate E-Cad:GFP structures. Symmetric phase, asymmetric phase, and MF depicted as in (A). (D) Apical top view of a dividing cell (asterisk) expressing E-Cad:GFP and MyoII:ChFP. Arrows: deformation of the E-Cad:GFP belt at the division plane. Open arrowheads: local disruption of the E-Cad:GFP belt. Arrowheads: E-Cad:GFP punctate structures. Yellow dotted box: region used to generate the kymograph in E. Symmetric phase, asymmetric phase and MF depicted as in A. See also Movie S2. (E) Kymograph of the cell shown in D. Left schematic: region used for the generation of the kymograph. Arrowhead: static E-Cad:GFP cluster. AP: Asymmetric phase; SP: Symmetric phase; MF: Midbody formation. (F and G) Quantification of the mean E-Cad:GFP intensity along the prospective interface between the daughter cells (F) (average, solid line ± SD, shaded domain, n = 32) and the interface length (average, solid line ± SD, shaded domain, n = 32) during cytokinesis. Scale bars, 5 μm. Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions

Figure 2 MyoII Accumulates in the Neighboring Cells during the Juxtaposition of the Dividing Cell Membrane (A) Apical top view of a tissue expressing E-Cad:GFP and MyoII:ChFP. T = 0: time of laser ablation. Yellow shaded domain: ablated region. Asterisk: dividing cell. Arrow: daughter cell interface after division. See also Movie S3. (B) Apical top view of a tissue expressing E-Cad:GFP and MyoII:ChFP. T = 0: time of laser ablation. Yellow shaded domain: ablated region. Asterisk: dividing cell. n: neighboring cells. Arrowheads: MyoII:ChFP accumulation in neighboring cells. Arrow: daughter cell interface after division. (C) Apical top view of a dividing cell (asterisk) expressing MyoII:ChFP and PH:GFP. Brackets: space in between the two portions of the furrow. Arrowheads: MyoII:ChFP accumulation adjacent to the furrow. Compare the furrow at t = 175 s and at t = 238 s to observe membrane juxtapostion. See also Movie S4. (D) Apical top view of a MyoII:ChFP//MyoII:GFP patch during the cytokinesis of MyoII:ChFP dividing cell (d) (n = 17 patches). The corresponding kymograph generated from the dotted yellow box is shown on the right. The dividing cell is only labeled by MyoII:ChFP and its neighbor (n) on the bottom only by MyoII:GFP. Arrowheads: MyoII:GFP accumulation in the neighboring cell. See also Movie S5. Scale bars, 5 μm. See also Figure S1. Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions

Figure 3 MyoII and Rok Are Required in the Neighboring Cells to Control the Length of the New AJ (A) Apical top view of a MyoII:ChFP and PH:GFP expressing tissue. T = 0: time of laser ablation. Yellow dotted circle: ablated region. Bracket: separation of the juxtaposed portions of the furrow upon laser ablation (13 of the 16 performed ablations). Arrowheads: reaccumulation of MyoII:ChFP in the ablated cell and reapposition of the dividing cell membrane. See also Movie S6. (B) Apical top view of a PH:GFP expressing tissue where a WT dividing cell (t = 0, d) has a WT neighbor on one side (WT) and a sqhAX3 neighbor on the other (sqh, dashed yellow outline). sqhAX3 cells were identified by loss of nls:mRFP (not shown). Dot: membrane juxtaposition at the WT side. Bracket: absence of membrane juxtaposition at the sqh side. (C) Apical top view of a E-Cad:GFP and MyoII:ChFP expressing tissue where a WT dividing cell (d) has a WT neighbor on one side (WT) and a rok2 neighbor on the other (rok, dashed yellow outline). rok2 cells were identified by loss of nls:GFP. Arrowheads: MyoII:ChFP accumulation at the WT side. Open arrowheads: absence of MyoII:ChFP accumulation at the rok side (12 of the 15 rok2 neighboring cells analyzed). Dot: a flat angle is formed at the edge of the interface at the WT side. Bracket: the angle remains open at the rok side. (D) Plot of the quantification of the interface length between the prospective daughter cells during cytokinesis in WT dividing cells having WT neighbors (average, blue solid line, ± SD, shaded domain, n = 32) and in WT dividing cells having a sqhAX3 neighbor (average, red solid line, ± SD, shaded domain, n = 15). (E and F) Histograms of the distributions of the interface length at midbody formation (E) and of the final AJ length between the daughter cells after division (F) in WT dividing cells with WT neighbors (blue, average ± SD, n = 32), and in WT dividing cells with a sqhAX3 neighbor (red, average ± SD, n = 15). The distributions of WT versus sqhAX3 neighbors are statistically different (p < 2 × 10−4 for E and p < 0.03 for F). (G) Same as (D), but showing in red WT dividing cells having a rok2 mutant neighbor (n = 17). (H and I) Same as (E and F) but showing in red WT dividing cells having a rok2 neighbor (n = 17). The interface length distributions of WT versus rok2 neighbors are statistically different (p < 3 × 10−4 for H and p < 0.022 for I). (J and K) Plots of the quantification of the angles at the edges of the prospective interface between the daughter cells during division (see scheme in L), in WT dividing cells facing a WT neighbor (J and K, average, blue solid line, ± SD, shaded domain, n = 10), facing a sqhAX3 neighbor (J, average, red solid line, ± SD, shaded domain, n = 8) or facing a rok2 neighbor (K, average, red solid line, ± SD, shaded domain, n = 11). At midbody formation, the WT versus sqh angles as well as the WT versus rok angles are significantly different (p < 6 × 10−5 and p < 3 × 10−3, respectively). (L) Schematics of the measured interface lengths and angles. Scale bars, 5 μm. See also Figure S2. Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions

Figure 4 Withdrawal of the Neighboring Cell Membranes Is Associated with Actin Accumulation around the Midbody and the Daughter Cell Interface (A and B) Apical top view of a PH:ChFP//PH:GFP patch (n = 15 patches) during cytokinesis of a PH:GFP dividing cell (d) (A) and the corresponding kymograph (B), generated from the yellow boxed region in A. The dividing cell expresses only PH:GFP, while its neighbors (n) express PH:ChFP. Brackets: neighboring cell membrane. Dot: membrane juxtaposition. Arrows: daughter cell membranes become indistinguishable. Compare brackets at t = 192 and t = 384 s to observe neighboring cell withdrawal concomitant to the expansion of the daughter cell contact. See also Movie S7A. (C–E) Apical top view of a MyoII:ChFP and Utr:GFP labeled dividing cell (C) and the corresponding kymographs along the daughter cell interface (D, from yellow boxed region in C), and orthogonal to the daughter cell interface (E, from red boxed region in C). In C, arrowheads: apical Utr:GFP accumulation upon midbody formation; arrows: concentration of Utr:GFP around the midbody; brackets: concentration of Utr:GFP at the daughter cell interface. In E, brackets: progressive concentration of Utr:GFP at the daughter cell interface and the midbody. See Figure S3 for quantification of MyoII:ChFP and Utr:GFP intensities along the daughter cell interface. See also Movie S8. (F and G) Apical top view of PH:ChFP labeled neighboring cells (n) within a tissue ubiquitously expressing Utr:GFP (n = 10) (F) and the corresponding kymograph (G) generated from the yellow boxed region in (F). In (F), arrowheads: Utr:GFP accumulation in the dividing cell; arrow: concentration of Utr:GFP at the daughter cell interface. In (G), brackets: neighboring cell membrane; arrow: Utr:GFP concentration at the interface. See also Movie S7B. Scale bars, 5 μm. Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions

Figure 5 The Midbody Can Act as a Cue to Orient the Apical Actin Accumulation (A) Apical top view of a MyoII:ChFP and Utr:GFP expressing tissue. T = 0: time of laser ablation. Yellow dotted circles: ablated regions. Brackets: separation of the juxtaposed membranes of the dividing cell upon ablation. Arrowheads: Utr:GFP accumulation and concentration at the daughter cell interface. (B) Time-lapse images of dividing cells expressing MyoII:ChFP and Utr:GFP, showing the front view of the cytokinetic ring (see schematic on the left). Upper panels: pupal dorsal thorax (notum). Lower panels: pupal wing (wing). Arrow: midbody. Arrowheads: Utr:GFP accumulation around the midbody. (C and D) Plots of the mean MyoII:GFP intensity (C) and the lengths (D) of the apical (blue) and basal (red) domains of the contractile ring (average ± SD, n = 10) in the pupal wing tissue. Apical and basal rings defined as in Figure 1B. (E) Schematics of the orientation of the mitotic spindle in WT (top) and mudFo1205 (bottom) dividing cells. Black dotted lines: cell division plane. (F) Time-lapse images showing the front view of the cytokinetic ring in a mudFo1205 cell expressing MyoII:ChFP and Utr:GFP. Arrows: midbody. Arrowheads: Utr:GFP accumulation around the midbody. Scale bars, 5 μm. Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions

Figure 6 Rac and Arp2/3 Regulate the Actin Accumulation and the Formation of a Long Interface between the Daughter Cells (A) Apical top view of a WT dividing cell expressing Arp3:GFP and Utr:ChFP (white dotted contour). (B) Apical top view of a arp3515FC dividing cell (white dotted contour) expressing Utr:GFP. The arp3515FC cell was identified by loss of nls:GFP signal. Compare with the WT cell in A. See also Figure S4A and Movie S9. (C and D) Apical top view of a arp3515FC dividing cell expressing E-Cad:GFP and MyoII:ChFP (C), and the corresponding kymograph (D), generated from the yellow boxed region in C. Arrowheads: MyoII:ChFP accumulation in neighboring cells. Asterisks: daughter cells. Arrow: daughter cell interface. (E) Apical top view of a arp3515FC cell after division expressing E-Cad:GFP and MyoII:ChFP. Asterisks: daughter cells. Arrow: interface between neighboring cells (n). (F) Plot of the quantification of the length of the prospective daughter cell interface during division in WT dividing cells (average, blue solid line ± SD, shaded domain, n = 32) and in arp3515FC mutant dividing cells (average, red solid line ± SD, shaded domain, n = 31). (G and H) Histograms of the distributions of the interface length at midbody formation (G) and of the final AJ length between the daughter cells after division (H), in WT (blue, average ± SD, n = 32) and arp3515FC (red, average ± SD, n = 31) dividing cells. At midbody formation, the length distributions of WT versus arp3515FC are not statistically different (G, p = 0.094). The distributions of the final AJ length of WT versus arp3515FC are statistically different (H, p < 2.5 × 10−4). (I) Apical top view of a WT (upper panels) and a rac1J11, rac2Δ, mtlΔ/+ (lower panels) dividing cell (white contour) expressing Arp3:GFP. Arrowheads: Arp3:GFP accumulation near the daughter cell interface. Arrow: Arp3:GFP accumulation at the midbody. No accumulation is observed in the rac1J11, rac2Δ, mtlΔ/+ cell (seven of seven cells). (J) Apical top view of a rac1J11, rac2Δ, mtlΔ/+ dividing cell expressing Utr:GFP (white dotted outline). Compare with the WT cell in A. See also Figure S4A. (K) Apical top view of a rac1J11, rac2Δ, mtlΔ/+ dividing cell expressing E-Cad:GFP and MyoII:ChFP. Arrowheads: MyoII:ChFP accumulation in neighboring cells. Asterisks: daughter cells. Arrows: interface between neighboring cells (n). See also Movie S10. Scale bars, 5 μm. Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions

Figure 7 Model for De Novo AJ Formation during Cytokinesis See discussion for details. Developmental Cell 2013 24, 256-270DOI: (10.1016/j.devcel.2012.11.019) Copyright © 2013 Elsevier Inc. Terms and Conditions