Figure 5.

IKNM Occurs in the Complete Absence of Microtubules

(A) Images of Movie S10. Polymerizing MTs are stained by EB3. Colcemide-treated (20 μM) embryos show reduced MT polymerization starting 120 min after drug addition. Shortly after drug addition, spindles are still formed and cells divide (arrow). Colcemide treatments of 120 min and longer arrest cells in metaphase for the rest of the observation time (arrowheads).

(B) Antibody staining of α-tubulin (red) and acetylated tubulin (green) like in Figure 2C in embryos treated with 20 μM Colcemide. Acetylated tubulin antibodies label stable basal bodies (asterisks), but no other stable structures are seen (a). α-tubulin antibodies label cytoplasmic tubulin (b). A merge of (a) and (b) is shown in (c). Asterisks label stable basal bodies that are only stained by acetylated not by α-tubulin.

(C) Images of Movie S11. H2B-RFP-labeled nuclei are able to move in apical and basal direction in epithelia treated with 20 μM Colcemide, indicated by white lines between false colored red and yellow nuclei and the basal membrane of the epithelium.

(D) Images of Movie S12. Nuclei still undergo rapid apical migration before forming a metaphase plate as seen in the control cells.

Scale bars represent 10 μm.