Extended Data Fig. 8: Additional characterization of spindle and ring formation.
From: A monoastral mitotic spindle determines lineage fate and position in the mouse embryo
a, Immunofluorescence for α-tubulin in embryos treated with Cytochalasin D. Disruption of the cortical actin by drug treatment triggers the formation of multiple ectopic MTOCs. b, Live-imaging of Utr-GFP and RFP-MAP2C in intact embryo shows a lack of correlation between the apical domain’s size and the orientation of the mitotic spindle. Note how the apical spindle pole does not preferentially target the border of the apical domain. Moreover, the spindle shown is aligned relatively orthogonal in a cell displaying a larger apical domain. This contrasts with models suggesting that a small apical domain determines orthogonal spindle positioning. c, Live-imaging of RFP-Utr and H2B-GFP in an intact embryo shows an additional example of apical domains disassembly during mitosis. d, Graph shows the number of inner-cells in the 16-cell stage embryos. Embryos treated with SiR-actin produce more inner-cells than controls. The centre line is the median, box edges show upper and lower quartiles and whiskers represent the range. **p = 0.0019; Two-tailed Mann Whitney U-test was used to test significance. e, Live-imaging of EB3-Tomato injected with Pard6b siRNA. Note that distal-MTOC origin from the cell-cell junctions (lateral MTOC) instead of the apical cortex, compared to Fig. 2c and Extended Data Fig. 2f,g,k. Scale bars, 10 µm. Source numerical data are provided in source data.
