Movie 1 An untreated control GFP-tubulin S2 cell from progresses from having a metaphase spindle to forming a stable intercellular bridge. Frame number and time (hours:minutes:seconds) are displayed at the bottom. The movie begins 00:06:39 before the start of the sequence in .
Movie 2 Untreated control GFP-tubulin S2 cell from . The movie shows that the intercellular bridge persists for a long time and that changes in its morphology and staining accompany its maturation. Note that, while the thin bridge goes in and out of focus, it appears to persist to the end of the movie.
Movie 3 Latrunculin A treatment: GFP-tubulin S2 cell to which 1 mg/ml LatA was added shortly after furrowing, as indicated (time = 00:34:00). Movie begins 00:26:30 before the start of the sequence in . Note the disruption of the microtubule bundle of the bridge and subsequent fusion of the cells.
Movie 4 Latrunculin A treatment: GFP-tubulin S2 cell to which 1 mg/ml LatA was added shortly after furrowing, as indicated here by frame number (frame 53 = time 00:26:52). Movie begins 00:08:16 before the start of the sequence in . Note the gradual reduction in the intensity of the focus of tubulin-GFP staining and the lack of fusion.
Movie 5 Two days of anillin RNAi: The GFP-tubulin S2 cell from , showing normal mitosis and cytokinesis furrow ingression, followed by a first phase of rampant blebbing in the cortex flanking the bridge (about 00:13:00 to 00:30:00). The central spindle initially became compacted, but the compacted microtubules of the bridge eventually disintegrated, gradually, as a new phase of blebbing occurred (starting at about 00:49:00). The blebbing subsided, the furrow gradually regressed, and the cells fused (01:10:00 to end). Movie begins 00:04:00 before the sequence in .
Movie 6 Three days of citron-kinase RNAi: The GFP-tubulin S2 cell from shows normal mitosis and cytokinesis furrow ingression, followed by formation of an intercellular bridge that thinned and matured normally. Although otherwise normal, the early stage of cytokinesis was accompanied by transient blebbing (00:19:57 – 00:57:45). At a late stage, after the blebbing subsided and the tubulin staining had dramatically declined (normal feature of bridge maturation), the furrow rapidly regressed (02:02:51). For this and subsequent movies, the first frame of the movie corresponds to the first panel of the corresponding figure.
Movie 7 Two days of alpha-SNAP RNAi: The GFP-tubulin S2 cell, showing paired sister cells fusing 5 hr after the start of the movie. Note the transfer of cytoplasmic material between sisters prior to cell fusion. Because mitosis and furrow ingression preceded the start of the movie, we can only say that the fusion occurred more than 5 hr after cytokinesis.
Movie 8 Two days of alpha-SNAP RNAi: GFP-tubulin S2 cells showing very late fusion of connected sister cells (one at 03:45:00 and one at 07:45:00).
Movie S9 Control Pav-GFP cell from : The marker protein labels the midbody throughout the 4 hr duration of the movie.
Movie S10 Two days of anillin RNAi: Pav-GFP cell, showing the late disruption of the midbody amid extensive membrane blebbing.
Movie S11 Three days of citron-kinase RNAi: Pav-GFP cell, showing the disruption of the midbody. Although the cell surface is only faintly visible in the video, it rapidly regresses shortly after the midbody staining shows initial evidence of decompaction.