Microtubule and microfilament cytoskeletons play key roles in the whole process of cytokinesis. Although a number of hypotheses have been proposed to elucidate the mechanism of cytokinesis by microtubule and actin fil...Microtubule and microfilament cytoskeletons play key roles in the whole process of cytokinesis. Although a number of hypotheses have been proposed to elucidate the mechanism of cytokinesis by microtubule and actin filament cytoskeletons, many reports are conflicting. In our study, combining the cytoskeletons drug treatments with the time-lapse video technology, we retested the key roles of microtubule and actin filament in cytokinesis. The results showed that depolymerization of microtubules by Nocoda- zole after the initiation of furrowing would not inhibit the furrow ingression, but obviously decrease the stiffness of daughter cells. Depolymerizing actin filaments by Cyto- chalasin B before metaphase would inhibit the initiation of furrowing but not chromosome segregation, resulting in the formation of binucleate cells; however, depolymerizing actin filaments during anaphase would prevent furrowing and lead to the regress of established furrow, also resulting in the formation of binucleate cells. Further, depolymerizing microtubules and actin filaments simultaneously after meta- phase would cause the quick regress of the furrow and the formation of binucleate cells. From these results we propose that a successful cytokinesis requires functions and coordina- tion of both the microtubule and actin filamentcytoskeletons. Microtubule cytoskeleton may function in the positioning and initiation of cleavage furrow, and the actin filament cy- toskeleton may play key roles in the initiation and ingression of the furrow.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grants Nos.30225016 and 30330200)the National Basic Research Program(Grants Nos.GI 999053908,2004CB720003)+1 种基金the Peking University Special Funds(985)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.
文摘Microtubule and microfilament cytoskeletons play key roles in the whole process of cytokinesis. Although a number of hypotheses have been proposed to elucidate the mechanism of cytokinesis by microtubule and actin filament cytoskeletons, many reports are conflicting. In our study, combining the cytoskeletons drug treatments with the time-lapse video technology, we retested the key roles of microtubule and actin filament in cytokinesis. The results showed that depolymerization of microtubules by Nocoda- zole after the initiation of furrowing would not inhibit the furrow ingression, but obviously decrease the stiffness of daughter cells. Depolymerizing actin filaments by Cyto- chalasin B before metaphase would inhibit the initiation of furrowing but not chromosome segregation, resulting in the formation of binucleate cells; however, depolymerizing actin filaments during anaphase would prevent furrowing and lead to the regress of established furrow, also resulting in the formation of binucleate cells. Further, depolymerizing microtubules and actin filaments simultaneously after meta- phase would cause the quick regress of the furrow and the formation of binucleate cells. From these results we propose that a successful cytokinesis requires functions and coordina- tion of both the microtubule and actin filamentcytoskeletons. Microtubule cytoskeleton may function in the positioning and initiation of cleavage furrow, and the actin filament cy- toskeleton may play key roles in the initiation and ingression of the furrow.
