Figure 5.

Cell migration regulates the kinetics of ingression. (A) The kinetics of ingression, defined as the time between formation of the metaphase plate until completion of the cleavage furrow, was assessed by timelapse microscopy. The β1-blocking MAB17781 (MAB) or control IgG isotype antibodies were added to sub-confluent culture of attached HeLa cells 5 hr post-seeding. (B) Tabulated results from experiments in (A) and represented as mean ± SEM (p < 0.001, χ² test) have been presented. The numbers above the column indicate the total number of cells analyzed. (C) Hoechst nuclear dye (blue) and β-tubulin specific antibody (red) were used to show various stages of mitosis/cytokinesis in HeLa cells. (D) Sub-confluent HeLa cells were exposed to MAB17781 or control IgG for 48 hr, fixed and stained for β-tubulin and Hoechst nuclear stain. Note that exposure to MAB17781 prevents cell spreading and culminates in groups of HeLa cells in tight aggregates. (E) Tabulated results from experiments in (D) are presented, indicating that MAB treatment results in a significant increase (p < 0.001, χ² test) in cells that have accumulated in metaphase through to telophase. The numbers above the column indicate the total number of cells analyzed. These data are in agreement with the results in (A and B) and support the notion that cell migration regulates furrowing kinetics.