Overview Cell Structures Cell Migration Cell Division  

Regulation of Anaphase Spindle Dynamics and Cytokinesis by CDK1 Inactivation

Wheatley et al., J. Cell Biol. 138:385-393 (1997)

CDK1 functions as a master regulator of mitosis. It is activated by cyclin B upon the entry into mitosis and inactivated during anaphase onset with the degradation of cyclin B. To identify events during anaphase and telophase that depend on CDK1 inactivation, an active, non-degradable cyclin B domain was expressed in dividing Normal Rat Kidney cells by the microinjection of its mRNA.

Sustained CDK1 Activities Cause Unregulated Chromosome Separation and Inhibition of Cytokinesis

Sustained CDK1 activities have no effect on the timing of chromosomal separation. However unlike in control cells, separated chromosomes in these cells continue to move until they hit the distal cortex, where they often bounce back to the central region of the cell. Cytokinesis also fails. Recording time, 21 min (upper) and 19 min (lower).



Sustained CDK1 Activities Cause Inhibition of the Formation of a Spindle Midzone

Cells microinjected with rhodamine tubulin show exaggerated spindle pole separation. Midzonal microtubules never assembled in these cells. Recording time, 20 min.