During cell mitosis

During animal cell mitosis the g-TURC complex is lost from spindle poles so the minus end of spindle microtubules can depolymerise while the plus end continues to polymerise. This behaviour, called microtubule flux, aids the establishment of chromosome bi-orientation (sister chromatids are attached to MTs from opposite spindle poles) and the speed at which they separate at anaphase. Microtubule flux can be observed by fluorescence speckle microscopy (FSM) when some, but not all, of the tubulin molecules in the cell are fluorescently labelled with GFP. During live cell imaging speckles of fluorescence can be seen to moving polewards during prometaphase, metaphase and anaphase. However, spindle microtubule length remains constant.