Chromosome movement during meiotic prophase in crane-fly spermatocytes: IV. Actin and the effects of cytochalasin D

LaFountain, James R.; Siegel, Alan J.; Rickards, Geoffrey K.

doi:10.1002/(sici)1097-0169(1999)43:3<199::aid-cm3>3.0.co;2-t

Cited by 5 publications

(1 citation statement)

References 34 publications

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“…When we incubated rec8⌬ meiocytes with cytochalasin D, which also inhibits actin polymerization (Peterson and Mitchison, 2002), there was a 1-h delay of telomere dispersion relative to the addition of the drug (the same effect as with Lat B), possibly owing to the reduced cell permeability of cytochalasin D (Greer and Schekman, 1982). Because vegetative telomere movements were not affected by the inhibition of actin polymerization (unpublished data), our observations suggest a novel role for actin in bringing about and maintaining meiotic telomere clustering, which is distinct from its known role in meiosis I division (Forer and Pickett-Heaps, 1998;LaFountain et al, 1999).…”

Section: Meiotic Telomere Clustering In S Cerevisiae Requires Actinmentioning

confidence: 65%

Meiotic telomere clustering requires actin for its formation and cohesin for its resolution

Trelles-Sticken

Adelfalk

Loidl

et al. 2005

The Journal of Cell Biology

141

197

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In diploid organisms, meiosis reduces the chromosome number by half during the formation of haploid gametes. During meiotic prophase, telomeres transiently cluster at a limited sector of the nuclear envelope (bouquet stage) near the spindle pole body (SPB). Cohesin is a multisubunit complex that contributes to chromosome segregation in meiosis I and II divisions. In yeast meiosis, deficiency for Rec8 cohesin subunit induces telomere clustering to persist, whereas telomere cluster–SPB colocalization is defective. These defects are rescued by expressing the mitotic cohesin Scc1 in rec8Δ meiosis, whereas bouquet-stage exit is independent of Cdc5 pololike kinase. An analysis of living Saccharomyces cerevisiae meiocytes revealed highly mobile telomeres from leptotene up to pachytene, with telomeres experiencing an actin- but not microtubule-dependent constraint of mobility during the bouquet stage. Our results suggest that cohesin is required for exit from actin polymerization–dependent telomere clustering and for linking the SPB to the telomere cluster in synaptic meiosis.

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Section: Meiotic Telomere Clustering In S Cerevisiae Requires Actinmentioning

confidence: 65%

Meiotic telomere clustering requires actin for its formation and cohesin for its resolution

Trelles-Sticken

Adelfalk

Loidl

et al. 2005

The Journal of Cell Biology

141

197

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Chromosome attachment to the spindle in crane-fly spermatocytes requires actin and is necessary to initiate the anaphase-onset checkpoint

Silverman-Gavrila

Forer

2000

Protoplasma

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Summary.We investigated the possible involvement of actin in the attachment of chromosomes to spindles in crane-fly primary spermatocytes. In a previous study, cytochalasin D, an inhibitor of actin polymerisation, prevented bivalent attachment to mierotubules when applied at prophase, but did not cause the detachment of already attached bivalents. We were able to detach the already attached bivatents by first treating prometaphase cells with an antitubulin drug, nocodazole, to disrupt spindle microtubules. 2 rain after nocodazole addition, W e added cytochalasin D, to disrupt actin filaments; then 2 rain later nocodazole was removed, and the cells were kept i n cytochalasin D until the time of normal anaphase. Double treatment with nocodazole and cytochalasin D blocked reattachment of bivalents to the spindle. Single treatment with nocodazole alone caused chromosome detachment but did not prevent reattachment when nocodazole was washed out. Extended treatment with cytochalasin D alone starting in prometaphase did not cause bivalents to detach from the spindle. These data suggest that actin is needed for attachment of bivalents to spindle microtubules. This protocol is relevant to the anaphase-onset checkpoint. From previous experiments it was argued that the anaphase-onset checkpoint recognises unattached chromosomes only after those chromosomes first interact with (become attached to) the spindle. Our experiments showed that anaphase disjunction occurred at normal times when bivalents were prevented from attaching to the spindle (by adding cytochalasin D in prophase), while anaphase disjunction was greatly delayed when previously attached bivalents were detached (with nocodazole) and then prevented from re-attaching (with cytochalasin D) in the double treated cells. Thus the anaphaseonset checkpoint recognises only those unattached bivalents that previously were attached to the spindle. Other results provided further indication that actin-microtubule interactions are important in spindle organisation. Nocodazole treatment for 4 rain caused most microtubules to disappear: bivalents aggregated around remnant microtubules. When cytochalasin D treatment followed nocodazole treatment, remnant spindle microtubules were not seen, suggesting that actin interactions help stabilise those microtubules.

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Localization of myosin II to chromosome arms and spindle fibers in PtK1 cells: a possible role for an actomyosin system in mitosis

Robinson

Snyder

2005

Protoplasma

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The enzymes of importance in moving chromosomes are called motor proteins and include dynein, kinesin, and possibly myosin II. These three molecules are all included in the category of ATPases, in that they have the ability to convert chemical energy into mechanical energy. Both dynein and kinesin have been documented as molecules that "walk" along microtubules in the mitotic spindle, carrying cargo such as chromosomes. Myosin II, analogous to the muscle contraction system, transiently interacts along actin filaments and associates with kinetochore microtubules. In this paper we present evidence that a third ATPase, myosin II, may act as a "thruster" to propel chromosomes during the mitotic process. Double-label immunocytochemistry to actin and myosin II shows that myosin II is localized on chromosome arms at the beginning of mitosis and remains localized to the chromosomes throughout mitosis. Specific staining of myosin II is relegated to the outside of chromosomes with the highest density of staining occurring between the spindle poles and the chromosomes. This specific localization could account for the movement of chromosomes during mitosis, since they segregate towards the spindle poles, along kinetochore microtubules containing actin filaments, after aligning at the equatorial region of the cell at metaphase. We conclude from this study that there is an actomyosin system present in the mitotic spindle and that myosin is attached to chromosome arms and may act as a thruster in moving chromosomes during the mitotic process.

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Chromosome movement during meiotic prophase in crane-fly spermatocytes: IV. Actin and the effects of cytochalasin D

Cited by 5 publications

References 34 publications

Meiotic telomere clustering requires actin for its formation and cohesin for its resolution

Meiotic telomere clustering requires actin for its formation and cohesin for its resolution

Chromosome attachment to the spindle in crane-fly spermatocytes requires actin and is necessary to initiate the anaphase-onset checkpoint

Localization of myosin II to chromosome arms and spindle fibers in PtK1 cells: a possible role for an actomyosin system in mitosis

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