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Budding yeast chromosome structure and dynamics during mitosis.

Pearson CG, Maddox PS, Salmon ED, Bloom K - J. Cell Biol. (2001)

Bottom Line: Centromeres are in a metaphase-like conformation, whereas chromosome arms are neither aligned nor separated before anaphase.The stretched chromatin was observed to segregate to the spindle pole bodies at rates greater than centromere to pole movement, indicative of rapid elastic recoil between the chromosome arm and the centromere.These results indicate that the elastic properties of DNA play an as of yet undiscovered role in the poleward movement of chromosome arms.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. cgpearso@email.unc.edu

ABSTRACT
Using green fluorescent protein probes and rapid acquisition of high-resolution fluorescence images, sister centromeres in budding yeast are found to be separated and oscillate between spindle poles before anaphase B spindle elongation. The rates of movement during these oscillations are similar to those of microtubule plus end dynamics. The degree of preanaphase separation varies widely, with infrequent centromere reassociations observed before anaphase. Centromeres are in a metaphase-like conformation, whereas chromosome arms are neither aligned nor separated before anaphase. Upon spindle elongation, centromere to pole movement (anaphase A) was synchronous for all centromeres and occurred coincident with or immediately after spindle pole separation (anaphase B). Chromatin proximal to the centromere is stretched poleward before and during anaphase onset. The stretched chromatin was observed to segregate to the spindle pole bodies at rates greater than centromere to pole movement, indicative of rapid elastic recoil between the chromosome arm and the centromere. These results indicate that the elastic properties of DNA play an as of yet undiscovered role in the poleward movement of chromosome arms.

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Upon anaphase onset chromosome spots exhibit rapid separation from their sister chromosome GFP spots at rates much greater than anaphase A and B movements. (A) Representative plot of sister chromatid spot separation for the ∼1.1-kb CEN11 marker upon anaphase onset. (B) Representative plot of sister chromatid separation for the ∼23-kb CEN3 marker upon anaphase onset. Sequences of rapid spot separation were acquired at single-plane, short acquisition intervals (>1 frame/s).
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Figure 6: Upon anaphase onset chromosome spots exhibit rapid separation from their sister chromosome GFP spots at rates much greater than anaphase A and B movements. (A) Representative plot of sister chromatid spot separation for the ∼1.1-kb CEN11 marker upon anaphase onset. (B) Representative plot of sister chromatid separation for the ∼23-kb CEN3 marker upon anaphase onset. Sequences of rapid spot separation were acquired at single-plane, short acquisition intervals (>1 frame/s).

Mentions: The centromere proximal spot was generally observed to separate at rates slightly greater than those observed for fast anaphase B spindle pole body separation. This is consistent with anaphase A and B movements being responsible for the rates of sister centromere separation (1.21 ± 0.46 μm/min; Table ). However, infrequently (3/16 observed; Table ), the initial rate of separation was observed to be much greater than that expected for the separation of sister chromatids (see above). Fig. 6 A shows initial separation of the ∼1.1-kb centromere proximal spots with a short rapid separation (arrow). These rates were 2.73–9.67 μm/min (average = 5.22 ± 3.87 μm/min; Table , initial separation) for a distance of 1.16 ± 0.22 μm (Table ). Although there was some evidence for chromatin recoil at the centromere proximal marker, it is not a frequent event with a significant contribution to chromosome poleward movement.


Budding yeast chromosome structure and dynamics during mitosis.

Pearson CG, Maddox PS, Salmon ED, Bloom K - J. Cell Biol. (2001)

Upon anaphase onset chromosome spots exhibit rapid separation from their sister chromosome GFP spots at rates much greater than anaphase A and B movements. (A) Representative plot of sister chromatid spot separation for the ∼1.1-kb CEN11 marker upon anaphase onset. (B) Representative plot of sister chromatid separation for the ∼23-kb CEN3 marker upon anaphase onset. Sequences of rapid spot separation were acquired at single-plane, short acquisition intervals (>1 frame/s).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199205&req=5

Figure 6: Upon anaphase onset chromosome spots exhibit rapid separation from their sister chromosome GFP spots at rates much greater than anaphase A and B movements. (A) Representative plot of sister chromatid spot separation for the ∼1.1-kb CEN11 marker upon anaphase onset. (B) Representative plot of sister chromatid separation for the ∼23-kb CEN3 marker upon anaphase onset. Sequences of rapid spot separation were acquired at single-plane, short acquisition intervals (>1 frame/s).
Mentions: The centromere proximal spot was generally observed to separate at rates slightly greater than those observed for fast anaphase B spindle pole body separation. This is consistent with anaphase A and B movements being responsible for the rates of sister centromere separation (1.21 ± 0.46 μm/min; Table ). However, infrequently (3/16 observed; Table ), the initial rate of separation was observed to be much greater than that expected for the separation of sister chromatids (see above). Fig. 6 A shows initial separation of the ∼1.1-kb centromere proximal spots with a short rapid separation (arrow). These rates were 2.73–9.67 μm/min (average = 5.22 ± 3.87 μm/min; Table , initial separation) for a distance of 1.16 ± 0.22 μm (Table ). Although there was some evidence for chromatin recoil at the centromere proximal marker, it is not a frequent event with a significant contribution to chromosome poleward movement.

Bottom Line: Centromeres are in a metaphase-like conformation, whereas chromosome arms are neither aligned nor separated before anaphase.The stretched chromatin was observed to segregate to the spindle pole bodies at rates greater than centromere to pole movement, indicative of rapid elastic recoil between the chromosome arm and the centromere.These results indicate that the elastic properties of DNA play an as of yet undiscovered role in the poleward movement of chromosome arms.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. cgpearso@email.unc.edu

ABSTRACT
Using green fluorescent protein probes and rapid acquisition of high-resolution fluorescence images, sister centromeres in budding yeast are found to be separated and oscillate between spindle poles before anaphase B spindle elongation. The rates of movement during these oscillations are similar to those of microtubule plus end dynamics. The degree of preanaphase separation varies widely, with infrequent centromere reassociations observed before anaphase. Centromeres are in a metaphase-like conformation, whereas chromosome arms are neither aligned nor separated before anaphase. Upon spindle elongation, centromere to pole movement (anaphase A) was synchronous for all centromeres and occurred coincident with or immediately after spindle pole separation (anaphase B). Chromatin proximal to the centromere is stretched poleward before and during anaphase onset. The stretched chromatin was observed to segregate to the spindle pole bodies at rates greater than centromere to pole movement, indicative of rapid elastic recoil between the chromosome arm and the centromere. These results indicate that the elastic properties of DNA play an as of yet undiscovered role in the poleward movement of chromosome arms.

Show MeSH
Related in: MedlinePlus