All cell culture-related reagents ChIP assay was carried out as previously described

tin is also influenced by the drug. Low concentration of Latrunculin A, a similar drug as Latrunculin B, is able to destroy cytoplasmic F-actin, but the completeness of cortical F-actin is conserved. Thus we concluded that the formation of ring-like F-actin structure and spindle positioning are two parallel events under the regulation of mitotic signals and Myosin. To discover the influence of the drugs on symmetric division, we measured the cell area ratio of daughter cells in anaphase. Compared with DMSO group, the area ratios of BI2536, Reversine and Latrunculin B groups are significantly different. However, Blebbistatin group has no significant difference. This may due to the stable spindle position of the cells treated with Blebbistatin. Although there are much more factors involved in the positioning of contractile ring, this ratio also suggests potential relations between the formation of ring-like structure and symmetric division. But the detailed pathway remains unclear. To address how the ring-like actin structure influences the spindle orientation, we measured the spindle angle and length of Mitotic Kinases Regulate F-Actin Dynamics 12 Mitotic Kinases Regulate F-Actin Dynamics metaphase arrested cells. Lat B and Blebbistatin groups do not have significant difference with DMSO group at the level of p,0.01, but Reversine, BI2536 and Nocodazole groups do. Spindles in BI2536 and Nocodazole groups are significantly shorter than control, while the spindle length in Reversine, Blebbistatin and Lat B groups has no significant difference from the control. These results suggest that spindle orientation is not significantly influenced by inhibiting Myosin motility or depolymerization of actin filament. The experimental concentration of Lat B may have very limited influence on cortical F-actin to alter spindle orientation in most cells we measured, which is consistent with previous publication. However, altered spindle orientation 181223-80-3 chemical information partially reflects the situation of cortical F-actin. Thus these are not crucial evidences to correlate ring-like structure formation with spindle position. Taken together, it remains unclear how these drugs influence the cortical stabilization. It PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19657107 is accepted that cortical complex influence spindle oscillation and positioning. On the other hand, spindle orientation is influenced by microtubule-cortex interaction. Thus, both the situations are related to the completeness of cortical complex. Lat B and Blebbistatin mainly affect cytoplasmic F-actin and more or less influence the function of cortical complex. The treatment of Blebbistatin and Lat B have major influence on the formation of the ring-like F-actin structure but have minor influence on cortical complex. On the contrary, Reversine and BI2536 treatment have major influence on cortical complex. . The spindle of Lat B treated cell deforms significantly. In Nocodazole treated cell, the spindle elongates and deforms, and it oscillates frequently. We had the 3D overview of the ring-like F-actin structure here. The result of Lat B treatment suggests that the perturbation of the ring-like F-actin structure is coupled with the altered configuration of spindle. The destruction of the structure may lead to uncontrolled spindle geometry rather than spindle length. The result of Blebbistatin treatment suggests that Myosin also functions in reducing the frequency of spindle oscillation. Discussion Accurate chromosome segregation in mitosis requires precise coordinat