JCS022897 Supplementary Material

Files in this Data Supplement:

• Supplemental Figure S1 -

  Fig. S1. Perforated, Zen-4-deficient zygote expressing GFP-myosin. (A) Frames from time-lapse sequence; scale bar=10 µm. In Frame 1, the metaphase spindle is visible to one side of the probe; asterisks mark approximate positions of spindle poles. ss, spindle side; fs, far side. In Frame 2 myosin patches are present on both spindle-side and far-side cortex. In Frame 3, the cortex around the probe has recruited myosin; this is gone in Frame 4 and returns in Frame 5. This proceeds for many iterations (Frame 6 and panel B). (B) Kymograph across the equator showing rapid, cyclical recruitment of myosin to the cortex around the probe. The cycle has a 20-second period. Horizontal scale bar=2 minutes, vertical scale=10 µm.

• Supplemental Figure S2 -

  Fig. S2. Results of spindle severing. In each panel, the dashed line indicates the cut site in Frame 1, and the spindle poles are indicated by arrowheads in Frame 2. (A) GFP-myosin-expressing embryo that manifests two furrows. The initial furrow progresses nearly to completion (Frames 3 and 4), but then a second furrow forms (Frame 5), which succeeds to separate the daughter nuclei (Frame 6). (B) GFP-myosin-expressing embryo that manifests a broad, sloppy furrow. Frames 3, 4 and 5 are focused at the surface to show the wide band of myosin recruited to the equatorial cortex. In Frame 3, a much broader-than-normal region of the cell surface has ingressed; by Frame 5 this has nearly resolved to a single furrow. (C) GFP-tubulin-expressing embryo similar to panel B; in Frame 3, more than a third of the surface on one side has become concave, but by Frame 5 this has resolved into a narrow ingression that bisects the spindle poles. Scale bar: 10 µm.

• Movie 1 -

  Movie 1. Perforation of wild-type zygote; movie corresponds to Fig. 1B. 15 frames per second at 2 seconds per frame=30× time compression. Anterior is to the left.

• Movie 2 -

  Movie 2. Laser-induced membrane fusion in a wild-type two-cell embryo expressing both GFP-tubulin and GFP-myosin; movie corresponds to Fig. 6B. 15 frames per second at 4 seconds per frame=60× time compression. Anterior is to the left.

• Movie 3 -

  Movie 3. Spindle severing in the zygote, creating an anucleate AB and binucleate P1; similar case to Fig. 7C. This embryo expresses both GFP-gamma tubulin and GFP-histone. The anterior spindle pole was cut off in metaphase. At anaphase, chromosomes separated but because this cell made no apparent attempt at a secondary furrow, both sets were segregated into P1. Duplicated centrosomes adopted opposite positions in AB, a furrow developed and ingressed deeply, then regressed as P1 entered metaphase. 15 frames per second at 4 seconds per frame=60× time compression. Anterior is to the left.