Depletion of topoisomerase IIα leads to shortening of the metaphase interkinetochore distance and abnormal persistence of PICH-coated anaphase threads

Spence, Jennifer M.; Phua, Hui Hui; Mills, Walter; Carpenter, Adam; Porter, Andrew C.G.; Farr, Carol L.

doi:10.1242/jcs.013730

Cited by 75 publications

(96 citation statements)

References 50 publications

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“…Instead, 44% of the ARHGAP19-deficient lymphocytes showed chromosome bridges occurring from the beginning of anaphase onset (in mild scenarios), or an apparent enlargement of the metaphasic chromosome plate as if sister chromatids were subject to forces pulling them apart but were not able to separate (in cells with the most severe phenotypes). These observations look similar to those described in cells with impaired topoisomerase II activity (which results in inhibition of DNA decatenation and physically prevents sister chromatid separation) (Spence et al, 2007). How the RhoA hyperactivation that results from depletion of ARHGAP19 might affect chromatin organisation or chromosome separation remains to be elucidated.…”

Section: Action Of Arhgap19 Throughout Cell Divisionsupporting

confidence: 81%

The RhoGAP ARHGAP19 controls cytokinesis and chromosome segregation in T lymphocytes

David

Petit

Bertoglio

2013

Journal of Cell Science

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Small GTP-binding proteins of the Rho family orchestrate the cytoskeleton remodelling events required for cell division. Guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) promote cycling of Rho GTPases between the active GTP-bound and the inactive GDP-bound conformations. We report that ARHGAP19, a previously uncharacterised protein, is predominantly expressed in hematopoietic cells and has an essential role in the division of T lymphocytes. Overexpression of ARHGAP19 in lymphocytes delays cell elongation and cytokinesis. Conversely, silencing of ARHGAP19 or expression of a GAPdeficient mutant induces precocious mitotic cell elongation and cleavage furrow ingression, as well as excessive blebbing. In relation to these phenotypes, we show that ARHGAP19 acts as a GAP for RhoA, and controls recruitment of citron and myosin II to the plasma membrane of mitotic lymphocytes as well as Rock2-mediated phosphorylation of vimentin, which is crucial to maintain the stiffness and shape of lymphocytes. In addition to its effects on cell shape, silencing of ARHGAP19 in lymphocytes also impairs chromosome segregation.

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Section: Action Of Arhgap19 Throughout Cell Divisionsupporting

confidence: 81%

The RhoGAP ARHGAP19 controls cytokinesis and chromosome segregation in T lymphocytes

David

Petit

Bertoglio

2013

Journal of Cell Science

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“…Indeed, previous RNAi of PICH results in an accumulation of binculeate cells, similar to the CAP-H KO phenotype (Kurasawa and Yu-Lee, 2010). It will be of interest, therefore, to ascertain whether there are PICHcoated anaphase fibres in CAP-H OFF cells persist as they do in topoisomerase-IIa-depleted cells (Spence et al, 2007) and whether the fibres are of arm, centromeric or telomeric origin.…”

Section: Cap-h Ko Cells Fail Cytokinesis Due To Persistence Of Anaphamentioning

confidence: 99%

Contrasting roles of condensin I and II in mitotic chromosome formation

Green

Kalitsis

Chang

et al. 2012

Journal of Cell Science

177

190

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SummaryIn vertebrates, two condensin complexes exist, condensin I and condensin II, which have differing but unresolved roles in organizing mitotic chromosomes. To dissect accurately the role of each complex in mitosis, we have made and studied the first vertebrate conditional knockouts of the genes encoding condensin I subunit CAP-H and condensin II subunit CAP-D3 in chicken DT40 cells. Live-cell imaging reveals highly distinct segregation defects. CAP-D3 (condensin II) knockout results in masses of chromatincontaining anaphase bridges. CAP-H (condensin I)-knockout anaphases have a more subtle defect, with chromatids showing fine chromatin fibres that are associated with failure of cytokinesis and cell death. Super-resolution microscopy reveals that condensin-Idepleted mitotic chromosomes are wider and shorter, with a diffuse chromosome scaffold, whereas condensin-II-depleted chromosomes retain a more defined scaffold, with chromosomes more stretched and seemingly lacking in axial rigidity. We conclude that condensin II is required primarily to provide rigidity by establishing an initial chromosome axis around which condensin I can arrange loops of chromatin.

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“…Loss of topoisomerase II (topo II) can reduce the interkinetochore distance in metaphase (Spence et al, 2007), and topo II can influence the longitudinal elasticity of mitotic chromosome arms (Kawamura and Marko, personal communication; Marko, 2008). Indeed, treatment with topo II inhibitor ICRF 159 slightly reduced the spacing between sister kinetochores, even in the presence of condensin (Figure 4e).…”

Section: Atpase Activity Of Condensin Is Essential For the Maintenancmentioning

confidence: 99%

“…However, SMC2 S1086R , a mutant capable of assembling a condensin complex that targets to chromosomes (Supplementary Figure S1) but that lacks ATPase activity (Hudson et al, 2008) failed to rescue the spacing between sister kinetochores (Figure 4e). Therefore, normal stiffness of the centromeric chromatin requires SMC2 ATPase activity.Loss of topoisomerase II (topo II) can reduce the interkinetochore distance in metaphase (Spence et al, 2007), and topo II can influence the longitudinal elasticity of mitotic chromosome arms (Kawamura and Marko, personal communication;Marko, 2008). Indeed, treatment with topo II inhibitor ICRF 159 slightly reduced the spacing between sister kinetochores, even in the presence of condensin (Figure 4e).…”

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confidence: 99%

Condensin Regulates the Stiffness of Vertebrate Centromeres

Ribeiro

Gatlin

Yang

et al. 2009

MBoC

Self Cite

140

147

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When chromosomes are aligned and bioriented at metaphase, the elastic stretch of centromeric chromatin opposes pulling forces exerted on sister kinetochores by the mitotic spindle. Here we show that condensin ATPase activity is an important regulator of centromere stiffness and function. Condensin depletion decreases the stiffness of centromeric chromatin by 50% when pulling forces are applied to kinetochores. However, condensin is dispensable for the normal level of compaction (rest length) of centromeres, which probably depends on other factors that control higher-order chromatin folding. Kinetochores also do not require condensin for their structure or motility. Loss of stiffness caused by condensindepletion produces abnormal uncoordinated sister kinetochore movements, leads to an increase in Mad2(؉) kinetochores near the metaphase plate and delays anaphase onset. INTRODUCTIONCentromeric chromatin is a special region of chromosomes that has important mechanical and signaling functions in mitosis (Pidoux and Allshire, 2005;Ekwall, 2007;Cheeseman and Desai, 2008;Vagnarelli et al., 2008). In metaphase, pulling forces generated by interactions between spindle microtubules (MTs) and kinetochores are opposed by tension produced by centromeric chromatin stretch. Centromere and kinetochore tension and stretch are important for maintaining chromosome alignment (McIntosh et al., 2002), stabilizing kinetochore microtubule (kMT) attachments (Nicklas and Koch, 1969), spindle checkpoint signaling (Musacchio and Salmon, 2007;McEwen and Dong, 2009), and also for the back-to-back orientation of sister kinetochores (Loncarek et al., 2007). At least three independent factors have roles in the establishment of centromeric tension in metaphase: sister chromatid cohesion (Yeh et al., 2008), the elastic properties of chromatin (Houchmandzadeh et al., 1997;Almagro et al., 2004;Marko, 2008), and the higher order structure of the centromeric chromatin.Condensin is important for the architecture of mitotic chromosome arms (Coelho et al., 2003;Hudson et al., 2003;Hirota et al., 2004;Hirano, 2006), but it also localizes to centromeres (Saitoh et al., 1994;Gerlich et al., 2006), where condensin I, but not condensin II was reported to have a role in stabilizing the structure (Gerlich et al., 2006). It has recently been suggested that condensin could have a role in regulating the elastic behavior of centromeric chromatin. One study found that condensin I-depleted Drosophila chromosomes were unable to align at a metaphase plate, had distorted kinetochore structures, and lost elasticity of their centromeric chromatin (Oliveira et al., 2005). However a similar study in human cells reported that although loss of condensin I caused kinetochores to undergo abnormal movements, these movements were bidirectional (e.g., reversible; Gerlich et al., 2006).Even after the publication of those results, the regulation and functional significance of centromere stretch remained unknown. An elegant study in budding yeast went on to find that chromatin struct...

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Depletion of topoisomerase IIα leads to shortening of the metaphase interkinetochore distance and abnormal persistence of PICH-coated anaphase threads

Cited by 75 publications

References 50 publications

The RhoGAP ARHGAP19 controls cytokinesis and chromosome segregation in T lymphocytes

The RhoGAP ARHGAP19 controls cytokinesis and chromosome segregation in T lymphocytes

Contrasting roles of condensin I and II in mitotic chromosome formation

Condensin Regulates the Stiffness of Vertebrate Centromeres

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