Mitosis and the Physiology of Cell Division

Mazia, Daniel

doi:10.1016/b978-0-12-123303-7.50008-9

Cited by 402 publications

(238 citation statements)

References 477 publications

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“…There is a range of anaphase velocities among different species from 0.2 ,um/min to 8 Am/min (20), but it is not yet clear whether this range is correlated with chromosome size . There has also been considerable speculation on the relationship between chromosome 55 2 THE JOURNAL OF CELL BIOLOGY " VOLUME 88,1981 size and the number of microtubules attached to the kinetochore.…”

Section: Discussionmentioning

confidence: 99%

Chromosome behavior after laser microirradiation of a single kinetochore in mitotic PtK2 cells.

McNeill¹,

Berns²

1981

The Journal of Cell Biology

129

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The role of the kinetochore in chromosome movement was studied by 532-nm wavelength laser microirradiation of mitotic PtK2 cells. When the kinetochore of a single chromatid is irradiated at mitotic prometaphase or metaphase, the whole chromosome moves towards the pole to which the unirradiated kinetochore is oriented, while the remaining chromosomes congregate on the metaphase plate. The chromatids of the irradiated chromosome remain attached to one another until anaphase, at which time they separate by a distance of 1 or 2 p,m and remain parallel to each other, not undergoing any poleward separation . Electron microscopy shows that irradiated chromatids exhibit either no recognizable kinetochore structure or a typical inactive kinetochore in which the tri-layer structure is present but has no microtubules associated with it . Graphical analysis of the movement of the irradiated chromosome shows that the chromosome moves to the pole rapidly with a velocity of -3 ,um/ min . If the chromosome is close to one pole at irradiation, and the kinetochore oriented towards that pole is irradiated, the chromosome moves across the spindle to the opposite pole . The chromosome is slowed down as it traverses the equatorial region, but the velocity in both half-spindles is approximately the same as the anaphase velocity of a single chromatid . Thus a single kinetochore moves twice the normal mass of chromatin (two chromatids) at the same velocity with which it moves a single chromatid, showing that the velocity with which a kinetochore moves is independent, within limits, of the mass associated with it .It is now generally accepted that mitotic spindle formation and chromosome movement involve several structures, including microtubules, centrioles, pericentriolar regions, and the centromere regions of the chromosomes . There have been several investigations into the ultrastructure and chemical composition of the kinetochore, or attachment site of microtubules to the centromeric region (14,(30)(31)(32)35) . Electron microscope studies have revealed a relatively uniform morphology of the kinetochore region in many different eukaryotes (including PtK 2 cells [34]) consisting of a trilaminar structure 0 .3-0 .6 ttm in diameter.Although the kinetochore has been demonstrated unequivocally to be a microtubule-organizing center in vitro (15,22,36,38), very little biochemical information is available on it . However, there are indications that ribonucleoprotein is a component of the kinetochore (9, 32) and it appears to be associated with the inner plate of the trilaminar kinetochore in PtK, cells .One of the earliest studies on the function of the centromere pertains to the mitotic behavior of x-ray-induced chromosome fragments lacking centromeres (11,12). Although these fragments did not join the metaphase plate, there was some sepa-THE JOURNAL OF CELL BIOLOGY " VOLUME 88 MARCH 1981 543-553 ©The Rockefeller University Press " 0021-9525/81/03/0543/11 $1 .00 ration of the chromatids at anaphase. However, they lagged behind the...

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Section: Discussionmentioning

confidence: 99%

Chromosome behavior after laser microirradiation of a single kinetochore in mitotic PtK2 cells.

McNeill¹,

Berns²

1981

The Journal of Cell Biology

129

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“…It has long been known that size is without influence on velocity during anaphase, and at least one researcher has recognized that this might be significant (17). However, this relationship has not previously been examined for the equally important congression movements in prometaphase.…”

Section: Introductionmentioning

confidence: 99%

Chromosome Velocity During Mitosis as a Function of Chromosome Size and Position

Nicklas

1965

The Journal of Cell Biology

100

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Chromosome velocity has been studied in living Melanoplus d~erentialis spermatocytes by phase contrast cinemicrography. Melanoplus chromosomes (and bivalents) differ in length by as much as 1:3.5. As expected, no size-dependent velocity differences were detected in anaphase, and this is also shown to be true for the less predictable movements during prometaphasc congression. The size of the X chromosome can change during observation following x-irradiation, but this is equally without influence on velocity. However, an effect of position on velocity is found in both prometaphase and in anaphase: the chromosomes furthest from the central interpolar axis move 25 per cent faster than more central chromosomes. A simple mechanical model relating frictional resistance and mitotic forces to chromosome velocity is discussed in detail. Calculations from the model suggest that a significant difference in the force acting on a large, as compared with a small chromosome is necessary to account for the observed similarity in velocity. Therefore, it is concluded that the mitotic forces are so organized or regulated that velocity is, within limits, independent of load. The implications of velocity-load independence in relation to the molecular origin of mitotic forces are discussed.

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“…Amongst many rather ingenuous theories put forward until mid-1950s, which attempted to explain anaphase chromosome movement by evoking currents, diffusion, tactoids, oscillating bodies, colloidal phenomena or electrical and magnetic forces (reviewed by [22,23]), the one based on fibrillar contractility [24,25], the classic "traction fiber" model, appeared the most appealing. According to this theory, chromosomes could approach the poles by contraction of k-fibers anchored to the pole.…”

Section: Anaphase a Modelsmentioning

confidence: 99%

The perpetual movements of anaphase

Maiato

Lince-Faria

2010

Cell. Mol. Life Sci.

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One of the most extraordinary events in the lifetime of a cell is the coordinated separation of sister chromatids during cell division. This is truly the essence of the entire mitotic process and the reason for the most profound morphological changes in cytoskeleton and nuclear organization that a cell may ever experience. It all occurs within a very short time window known as "anaphase", as if the cell had spent the rest of its existence getting ready for this moment in an ultimate act of survival. And there is a good reason for this: no space for mistakes. Problems in the distribution of chromosomes during cell division have been correlated with aneuploidy, a common feature observed in cancers and several birth defects, and the main cause of spontaneous abortion in humans. In this paper we critically review the mechanisms of anaphase chromosome motion that resisted the scrutiny of more than one hundred years of research as part of a tribute to the pioneering work of Miguel Mota.

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Mitosis and the Physiology of Cell Division

Cited by 402 publications

References 477 publications

Chromosome behavior after laser microirradiation of a single kinetochore in mitotic PtK2 cells.

Chromosome behavior after laser microirradiation of a single kinetochore in mitotic PtK2 cells.

Chromosome Velocity During Mitosis as a Function of Chromosome Size and Position

The perpetual movements of anaphase

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