Unusual Movement of the Daughter Chromosome Group in Telophasic Cells Following the Exposure to Ultraviolet Microbeam Irradiation

Nakanishi, Yuh H.; Kato, Hatao

doi:10.1508/cytologia.30.213

Cited by 11 publications

(4 citation statements)

References 6 publications

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“…It seems likely that tethers between partner chromosomes are responsible for the backwards movements observed after cutting individual anaphase spindle fibres in PtK cells (Elting et al, 2014), which have tethers (this paper), and, by extension, in grasshopper spermatocytes (Chen and Zhang, 2004) and newt fibroblasts (Spurck et al, 1997), in neither of which have tethers been demonstrated. We might also speculate that backwards movements seen after cutting across entire half-spindles in anaphase Haemanthus cells (Bajer, 1972) are due to tethers, and backwards movements after spindle poles are irradiated in silkworm meiosis-I (Nakanishi et al, 1965) are due to tethers.…”

Section: Discussionmentioning

confidence: 99%

Elastic ‘tethers’ connect separating anaphase chromosomes in a broad range of animal cells

Forer

Duquette

Paliulis

et al. 2017

European Journal of Cell Biology

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We describe the general occurrence in animal cells of elastic components ("tethers") that connect individual chromosomes moving to opposite poles during anaphase. Tethers, originally described in crane-fly spermatocytes, exert force on chromosome arms opposite to the direction the anaphase chromosomes move. We show that they exist in a broad range of animal cells. Thus tethers are previously unrecognised components of general mitotic mechanisms that exert force on chromosomes and they need to be accounted for in general models of mitosis in terms of forces on chromosomes and in terms of what their roles might be.

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Section: Discussionmentioning

confidence: 99%

Elastic ‘tethers’ connect separating anaphase chromosomes in a broad range of animal cells

Forer

Duquette

Paliulis

et al. 2017

European Journal of Cell Biology

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“…However, chromosome arms, severed with a laser beam, regularly moved backwards [95]. Backward movements were seen also in silkworm spermatocytes after UV irradiation of a spindle pole [103] : the chromosomes associated with the irradiated pole moved across the equator to the opposite pole. In grasshopper spermatocytes [104] there are fast backwards movements after UV irradiation of the kinetochore in early anaphase.…”

Section: Discussionmentioning

confidence: 99%

Calyculin A, an enhancer of myosin, speeds up anaphase chromosome movement

2007

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Actin and myosin inhibitors often blocked anaphase movements in insect spermatocytes in previous experiments. Here we treat cells with an enhancer of myosin, Calyculin A, which inhibits myosinlight-chain phosphatase from dephosphorylating myosin; myosin thus is hyperactivated. Calyculin A causes anaphase crane-fly spermatocyte chromosomes to accelerate poleward; after they reach the poles they often move back toward the equator. When added during metaphase, chromosomes at anaphase move faster than normal. Calyculin A causes prometaphase chromosomes to move rapidly up and back along the spindle axis, and to rotate. Immunofluorescence staining with an antibody against phosphorylated myosin regulatory light chain (p-squash) indicated increased phosphorylation of cleavage furrow myosin compared to control cells, indicating that calyculin A indeed increased myosin phosphorylation. To test whether the Calyculin A effects are due to myosin phosphatase or to type 2 phosphatases, we treated cells with okadaic acid, which inhibits protein phosphatase 2A at concentrations similar to Calyculin A but requires much higher concentrations to inhibit myosin phosphatase. Okadaic acid had no effect on chromosome movement. Backward movements did not require myosin or actin since they were not affected by 2,3-butanedione monoxime or LatruculinB. Calyculin A affects the distribution and organization of spindle microtubules, spindle actin, cortical actin and putative spindle matrix proteins skeletor and titin, as visualized using immunofluorescence. We discuss how accelerated and backwards movements might arise.

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“…UV microbeam experiments in silkworm spermatocytes suggested a function for persistent connections. Irradiation of one spindle pole in telophase I silkworm spermatocytes causes the entire chromosome group associated with the irradiated pole to move to the opposite spindle pole (Nakanishi, 1965). This result suggested that there was something applying force to separating chromosomes that opposed the anaphase poleward force.…”

Section: Functional Evidence For Tethersmentioning

confidence: 99%

A review of “tethers”: elastic connections between separating partner chromosomes in anaphase

Paliulis

Forer

2018

Protoplasma

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Recent work has demonstrated the existence of elastic connections, or tethers, between the telomeres of separating partner chromosomes in anaphase. These tethers oppose the poleward spindle forces in anaphase. Functional evidence for tethers has been found in a wide range of animal taxa, suggesting that they might be present in all dividing cells. An examination of the literature on cell division from the nineteenth century to the present reveals that connections between separating partner chromosomes in anaphase have been described in some of the earliest observations of cell division. Here, we review what is currently known about connections between separating partner chromosomes in anaphase, and we speculate on possible functions of tethers, and on what they are made of and how one might determine their composition.

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Unusual Movement of the Daughter Chromosome Group in Telophasic Cells Following the Exposure to Ultraviolet Microbeam Irradiation

Cited by 11 publications

References 6 publications

Elastic ‘tethers’ connect separating anaphase chromosomes in a broad range of animal cells

Elastic ‘tethers’ connect separating anaphase chromosomes in a broad range of animal cells

Calyculin A, an enhancer of myosin, speeds up anaphase chromosome movement

A review of “tethers”: elastic connections between separating partner chromosomes in anaphase

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