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Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle

During mitosis a monooriented chromosome oscillates toward and away from its associated spindle pole and may be positioned many micrometers from the pole at the time of anaphase. We tested the hypothesis of Pickett-Heaps et al. (Pickett-Heaps, J. D., D. H. Tippit, and K. R. Porter, 1982, Cell, 29:72...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1986
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2113830/
https://www.ncbi.nlm.nih.gov/pubmed/3733881
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description During mitosis a monooriented chromosome oscillates toward and away from its associated spindle pole and may be positioned many micrometers from the pole at the time of anaphase. We tested the hypothesis of Pickett-Heaps et al. (Pickett-Heaps, J. D., D. H. Tippit, and K. R. Porter, 1982, Cell, 29:729-744) that this behavior is generated by the sister kinetochores of a chromosome interacting with, and moving in opposite direction along, the same set of polar microtubules. When the sister chromatids of a monooriented chromosome split at the onset of anaphase in newt lung cells, the proximal chromatid remains stationary or moves closer to the pole, with the kinetochore leading. During this time the distal chromatid moves a variable distance radially away from the pole, with one or both chromatid arms leading. Subsequent electron microscopy of these cells revealed that the kinetochore on the distal chromatid is free of microtubules. These results suggest that the distal kinetochore is not involved in the positioning of a monooriented chromosome relative to the spindle pole or in its oscillatory movements. To test this conclusion we used laser microsurgery to create monooriented chromosomes containing one kinetochore. Correlative light and electron microscopy revealed that chromosomes containing one kinetochore continue to undergo normal oscillations. Additional observations on normal and laser-irradiated monooriented chromosomes indicated that the chromosome does not change shape, and that the kinetochore region is not deformed, during movement away from the pole. Thus movement away from the pole during an oscillation does not appear to arise from a push generated by the single pole-facing kinetochore fiber, as postulated (Bajer, A. S., 1982, J. Cell Biol., 93:33-48). When the chromatid arms of a monooriented chromosome are cut free of the kinetochore, they are immediately ejected radially outward from the spindle pole at a constant velocity of 2 micron/min. This ejection velocity is similar to that of the outward movement of an oscillating chromosome. We conclude that the oscillations of a monooriented chromosome and its position relative to the spindle pole result from an imbalance between poleward pulling forces acting at the proximal kinetochore and an ejection force acting along the chromosome, which is generated within the aster and half-spindle.
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spelling pubmed-21138302008-05-01 Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle J Cell Biol Articles During mitosis a monooriented chromosome oscillates toward and away from its associated spindle pole and may be positioned many micrometers from the pole at the time of anaphase. We tested the hypothesis of Pickett-Heaps et al. (Pickett-Heaps, J. D., D. H. Tippit, and K. R. Porter, 1982, Cell, 29:729-744) that this behavior is generated by the sister kinetochores of a chromosome interacting with, and moving in opposite direction along, the same set of polar microtubules. When the sister chromatids of a monooriented chromosome split at the onset of anaphase in newt lung cells, the proximal chromatid remains stationary or moves closer to the pole, with the kinetochore leading. During this time the distal chromatid moves a variable distance radially away from the pole, with one or both chromatid arms leading. Subsequent electron microscopy of these cells revealed that the kinetochore on the distal chromatid is free of microtubules. These results suggest that the distal kinetochore is not involved in the positioning of a monooriented chromosome relative to the spindle pole or in its oscillatory movements. To test this conclusion we used laser microsurgery to create monooriented chromosomes containing one kinetochore. Correlative light and electron microscopy revealed that chromosomes containing one kinetochore continue to undergo normal oscillations. Additional observations on normal and laser-irradiated monooriented chromosomes indicated that the chromosome does not change shape, and that the kinetochore region is not deformed, during movement away from the pole. Thus movement away from the pole during an oscillation does not appear to arise from a push generated by the single pole-facing kinetochore fiber, as postulated (Bajer, A. S., 1982, J. Cell Biol., 93:33-48). When the chromatid arms of a monooriented chromosome are cut free of the kinetochore, they are immediately ejected radially outward from the spindle pole at a constant velocity of 2 micron/min. This ejection velocity is similar to that of the outward movement of an oscillating chromosome. We conclude that the oscillations of a monooriented chromosome and its position relative to the spindle pole result from an imbalance between poleward pulling forces acting at the proximal kinetochore and an ejection force acting along the chromosome, which is generated within the aster and half-spindle. The Rockefeller University Press 1986-08-01 /pmc/articles/PMC2113830/ /pubmed/3733881 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle
title Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle
title_full Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle
title_fullStr Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle
title_full_unstemmed Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle
title_short Oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle
title_sort oscillatory movements of monooriented chromosomes and their position relative to the spindle pole result from the ejection properties of the aster and half-spindle
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2113830/
https://www.ncbi.nlm.nih.gov/pubmed/3733881