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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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Centromere dynamics of all chromosomes using the pan-specific centromere marker Cse4p fused to GFP (Cse4–GFP). Dynamic movements between the two clustered groups indicated a similar separation and dynamic movements to those observed for the ∼1.1-kb centromere proximal marker. Spindle pole bodies are not labeled. (A) Selected images of an ∼9-min single-plane time-lapse. (B) Kymograph of the entire time-lapse taken at 5-s intervals. Arrowheads in A and B indicate occurrences of GFP centromere fluorescence disjoining from the clustered group. Narrow tick marks indicate corresponding times to A. Elapsed time is in seconds. Bar, 2 μm.
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Figure 3: Centromere dynamics of all chromosomes using the pan-specific centromere marker Cse4p fused to GFP (Cse4–GFP). Dynamic movements between the two clustered groups indicated a similar separation and dynamic movements to those observed for the ∼1.1-kb centromere proximal marker. Spindle pole bodies are not labeled. (A) Selected images of an ∼9-min single-plane time-lapse. (B) Kymograph of the entire time-lapse taken at 5-s intervals. Arrowheads in A and B indicate occurrences of GFP centromere fluorescence disjoining from the clustered group. Narrow tick marks indicate corresponding times to A. Elapsed time is in seconds. Bar, 2 μm.

Mentions: To confirm the centromere oscillations observed using the ∼1.1-kb centromere proximal marker, we analyzed the movements of the pan-specific centromere marker Cse4–GFP. Fig. 3A and Fig. B, describes two distinct groups of centromeres at time point 145 s that separate into multiple spots, as observed with broader, less intense bands of fluorescence (Fig. 3 A, time point = 305 s, arrowheads), and then reassociate into two diffuse clusters or groups (Fig. 3 A, time point = 550 s). Transient Cse4–GFP movements were observed between the clustered groups of fluorescence (Fig. 3, arrowheads), indicating that centromeres exhibit dynamic movements relative to other centromeres in each clustered group. Furthermore, two-color imaging of Cse4–GFP with CFP-labeled spindle pole bodies shows that the centromeres move relative to the spindle pole bodies (data not shown).


Budding yeast chromosome structure and dynamics during mitosis.

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

Centromere dynamics of all chromosomes using the pan-specific centromere marker Cse4p fused to GFP (Cse4–GFP). Dynamic movements between the two clustered groups indicated a similar separation and dynamic movements to those observed for the ∼1.1-kb centromere proximal marker. Spindle pole bodies are not labeled. (A) Selected images of an ∼9-min single-plane time-lapse. (B) Kymograph of the entire time-lapse taken at 5-s intervals. Arrowheads in A and B indicate occurrences of GFP centromere fluorescence disjoining from the clustered group. Narrow tick marks indicate corresponding times to A. Elapsed time is in seconds. Bar, 2 μm.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 3: Centromere dynamics of all chromosomes using the pan-specific centromere marker Cse4p fused to GFP (Cse4–GFP). Dynamic movements between the two clustered groups indicated a similar separation and dynamic movements to those observed for the ∼1.1-kb centromere proximal marker. Spindle pole bodies are not labeled. (A) Selected images of an ∼9-min single-plane time-lapse. (B) Kymograph of the entire time-lapse taken at 5-s intervals. Arrowheads in A and B indicate occurrences of GFP centromere fluorescence disjoining from the clustered group. Narrow tick marks indicate corresponding times to A. Elapsed time is in seconds. Bar, 2 μm.
Mentions: To confirm the centromere oscillations observed using the ∼1.1-kb centromere proximal marker, we analyzed the movements of the pan-specific centromere marker Cse4–GFP. Fig. 3A and Fig. B, describes two distinct groups of centromeres at time point 145 s that separate into multiple spots, as observed with broader, less intense bands of fluorescence (Fig. 3 A, time point = 305 s, arrowheads), and then reassociate into two diffuse clusters or groups (Fig. 3 A, time point = 550 s). Transient Cse4–GFP movements were observed between the clustered groups of fluorescence (Fig. 3, arrowheads), indicating that centromeres exhibit dynamic movements relative to other centromeres in each clustered group. Furthermore, two-color imaging of Cse4–GFP with CFP-labeled spindle pole bodies shows that the centromeres move relative to the spindle pole bodies (data not shown).

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