It has long been known that during the closed mitosis of many unicellular eukaryotes, including the fission yeast (Schizosaccharomyces pombe), the nuclear envelope remains intact while the nucleus undergoes a remarkable sequence of shape transformations driven by elongation of an intranuclear mitotic spindle whose ends are capped by spindle pole bodies embedded in the nuclear envelope.
The correct separation of the chromosomes depends on a structure called the mitotic spindle whose location in the cell also determines where the point of division will be.
The air spindles whose shafts are made of carbon fiber composite are appropriate for high-speed and high-precision machining such as small hole drilling of printed circuit board (PCB) or wafer cutting for manufacturing semiconductors because the carbon fiber composite shaft has low rotational inertia, high damping ratio and high fundamental natural frequency.
Chromosome counts were carried out on live embryos in utero or on fixed embryos extruded from the worm by locating metaphase spindles whose chromosomes were all aligned at the metaphase plate.
Kinetochore microtubules (kMTs) are spindle microtubule whose minus ends are typically anchored at the spindle poles and whose plus ends terminate end-on at the kinetochore.
We identified the kinesin-13 kif2asas a driver of developmental spindle scaling whose microtubule-destabilizing activity is inhibited in stage 3 spindles by the transport receptor importin α, and activated in stage 8 when importin α partitions to a membrane pool.
One of these proteins is the Drosophila melanogaster DExH box/Tudor domain protein Spindle-E, whose activity is necessary for the generation of most germline piRNAs.
We found that bipolar CIN anaphase cells possessed merotelically attached lagging chromosomes (i.e., chromosomes that lagged behind at the spindle equator instead of segregating to the spindle pole, and whose kinetochore was bound to microtubule bundles from both spindle poles rather than just one; Figure 2C, right column) at higher frequencies than MIN cells (Figure 2B).
The last result suggests that within and among single fast 'up' states, occurring in the spindle oscillations regime, whose onset and decay are well synchronized across the recording sites, spatial organization of discharge patterns can be negligible or absent.
Kinetochores also host the spindle assembly checkpoint, whose effector, the mitotic checkpoint complex (MCC), prevents APC/C activation until all chromosomes have bioriented (reviewed in Musacchio and Salmon, 2007).
Cells are effectively arrested in prometaphase and a molecular device, the spindle assembly checkpoint (SAC), whose components localize at kinetochores, function as a "proofreading network" by creating a diffusible signal indispensable to delay anaphase progression thus ensuring the prevention of aberrant mitosis.
