Journal ArticleDOI
'Anaphase' and cytokinesis in the absence of chromosomes
Dahong Zhang,R. Bruce Nicklas +1 more
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TLDR
It is found that both anaphase and cytokinesis occur independently of chromosomes: stage-specific changes occur at an appropriate time and in the correct way, despite the absence of chromosomes.Abstract:
ANAPHASE and cytokinesis are key processes in the segregation of replicated chromosomes to the daughter cells: in anaphase, chromosomes move apart; in cytokinesis, a cleavage furrow forms midway between the separated chromosomes. Some evidence suggests that chromosomes may be involved both in controlling the timing of anaphase onset1–3 and in dictating the position of the cleavage furrow3. Other evidence indicates that the controlling mechanisms are intrinsic to the spindle and the cell4–7. Here we test these possibilities in grasshopper spermatocytes by observing spindles and cells after removal of chromosomes. We found that both anaphase and cytokinesis occur independently of chromosomes: stage-specific changes occur at an appropriate time and in the correct way, despite the absence of chromosomes. This finding is particularly noteworthy because chromosomes have an important impact on spindle microtubule assembly8,9 and the timing of anaphase onset10 in these cells.read more
Citations
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Journal ArticleDOI
Cell Cycle Checkpoints: Preventing an Identity Crisis
TL;DR: Signal transduction pathways that transmit checkpoint signals in response to DNA damage, replication blocks, and spindle damage are revealed, underscoring the conservation of cell cycle regulatory machinery.
Journal ArticleDOI
How proteolysis drives the cell cycle
TL;DR: Proteolysis drives cell cycle progression not only by regulating CDK activity, but by directly influencing chromosome and spindle dynamics, and also how proteolysis may directly trigger the transition from metaphase to anaphase.
Journal ArticleDOI
CENP-E forms a link between attachment of spindle microtubules to kinetochores and the mitotic checkpoint
TL;DR: In this article, it was shown that the absence of CENP-E (centromere-associated protein E), a component of the kinetochore corona fibres of mammalian centromeres, yields chromosomes that are chronically mono-orientated, with spindles that are flattened along the plane of the substrate.
Journal ArticleDOI
pavarotti encodes a kinesin-like protein required to organize the central spindle and contractile ring for cytokinesis
TL;DR: It is suggested that PAV-KLP is required both to establish the structure of the telophase spindle to provide a framework for the assembly of the contractile ring, and to mobilize mitotic regulator proteins.
Journal ArticleDOI
Visualization of Mad2 dynamics at kinetochores, along spindle fibers, and at spindle poles in living cells.
TL;DR: Kinetochore-derived sites along spindle fibers and at spindle poles may also catalyze Mad2 inhibitory complex formation, and several observations indicate that Mad2 binding sites are translocated from kinetochores to spindle Poles along microtubules.
References
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Journal ArticleDOI
The Cell In Development And Heredity
Journal ArticleDOI
Creative blocks: cell-cycle checkpoints and feedback controls
TL;DR: Before division, cells must ensure that they finish DNA replication, DMA repair and chromosome segregation by using feedback controls which can detect the failure to complete replication, repair or spindle assembly to arrest the progress of the cell cycle at one of three checkpoints.
Journal ArticleDOI
Mitotic forces control a cell-cycle checkpoint
Xiaotong Li,R. B. Nicklas +1 more
TL;DR: This work applies tension to an improperly attached chromosome with a micromanipulation needle and finds that the entry into anaphase and the completion of mitosis was delayed by 5–6 hours when the misattached chromosome was placed under tension.
Journal ArticleDOI
Anaphase is initiated by proteolysis rather than by the inactivation of maturation-promoting factor
TL;DR: The N-terminal cyclin fragment inhibits chromosome separation even in extracts that contain only nondegradable forms of cyclin, suggesting that proteins other than the known cyclins must be degraded to dissolve the linkage between sister chromatids.
Journal ArticleDOI
Anaphase onset in vertebrate somatic cells is controlled by a checkpoint that monitors sister kinetochore attachment to the spindle.
TL;DR: It is concluded that vertebrate somatic cells possess a metaphase-anaphase checkpoint control that monitors sister kinetochore attachment to the spindle, and that the chromosomes move poleward during anaphase.