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Aurora B prevents chromosome arm separation defects by promoting telomere dispersion and disjunction.

Reyes C, Serrurier C, Gauthier T, Gachet Y, Tournier S - J. Cell Biol. (2015)

Bottom Line: Dispersion is promoted by the dissociation of Swi6/HP1 and cohesin Rad21 from telomeres, whereas disjunction occurs at anaphase after the phosphorylation of condensin subunit Cnd2.Strikingly, we demonstrate that deletion of Ccq1, a telomeric shelterin component, rescued cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms.Our findings reveal an essential role for telomeres in chromosome arm segregation.

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Affiliation: Laboratoire de biologie cellulaire et moléculaire du contrôle de la prolifération, Université de Toulouse, F-31062 Toulouse, France Centre National de la Recherche Scientifique, LBCMCP-UMR5088, F-31062 Toulouse, France.

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Model summarizing the different state in telomere clustering throughout mitosis. Schematic representation illustrating the regulation of telomere dissociation throughout mitosis. (left) Telomere foci undergo separation in two discrete steps. Telomere cluster dispersion (up to 6 dots) occurs during metaphase, before chromosome segregation, whereas sister chromatid telomere disjunction (up to 12 dots) is achieved during mid-anaphase. Finally, telomere reclustering occurs during cytokinesis (subsequent G1/S phase). Aurora B is required for telomere dispersion and disjunction. (right) At the level of telomeres, Aurora promotes in metaphase the delocalization of several telomere/subtelomere components, such as shelterin components (brown), Swi6/HP1 (blue), or cohesin Rad21 (green). At anaphase, Aurora favors the loading of condensin (pink). Our model suggests that the delocalization of telomere components such as the shelterin protein Ccq1 promotes telomere dispersion and Aurora-dependent loading of condensin to chromosome arms.
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fig9: Model summarizing the different state in telomere clustering throughout mitosis. Schematic representation illustrating the regulation of telomere dissociation throughout mitosis. (left) Telomere foci undergo separation in two discrete steps. Telomere cluster dispersion (up to 6 dots) occurs during metaphase, before chromosome segregation, whereas sister chromatid telomere disjunction (up to 12 dots) is achieved during mid-anaphase. Finally, telomere reclustering occurs during cytokinesis (subsequent G1/S phase). Aurora B is required for telomere dispersion and disjunction. (right) At the level of telomeres, Aurora promotes in metaphase the delocalization of several telomere/subtelomere components, such as shelterin components (brown), Swi6/HP1 (blue), or cohesin Rad21 (green). At anaphase, Aurora favors the loading of condensin (pink). Our model suggests that the delocalization of telomere components such as the shelterin protein Ccq1 promotes telomere dispersion and Aurora-dependent loading of condensin to chromosome arms.

Mentions: Chromosome end protection in S. pombe is similar to that seen in mammals and a recent study has identified several proteins including Pot1 or Ccq1 that form the shelterin complex (Miyoshi et al., 2008). Ccq1 is the S. pombe–specific component of this complex and is required for telomerase recruitment (Moser et al., 2011; Yamazaki et al., 2012). Ccq1 also participates in the telomeric recruitment of a multi-enzyme complex (termed SHREC) that mediates heterochromatic transcriptional gene silencing (Sugiyama et al., 2007). The dissociation of shelterin components from telomeres during mitosis was previously demonstrated using chromatin immunoprecipitation (Chang et al., 2013). Our study provides the timing for this dissociation with respect to chromosome segregation and telomere dispersion. It also suggests that Aurora controls the dissociation of Pot1 or Ccq1 at the metaphase-to-anaphase transition (Fig. 9).


Aurora B prevents chromosome arm separation defects by promoting telomere dispersion and disjunction.

Reyes C, Serrurier C, Gauthier T, Gachet Y, Tournier S - J. Cell Biol. (2015)

Model summarizing the different state in telomere clustering throughout mitosis. Schematic representation illustrating the regulation of telomere dissociation throughout mitosis. (left) Telomere foci undergo separation in two discrete steps. Telomere cluster dispersion (up to 6 dots) occurs during metaphase, before chromosome segregation, whereas sister chromatid telomere disjunction (up to 12 dots) is achieved during mid-anaphase. Finally, telomere reclustering occurs during cytokinesis (subsequent G1/S phase). Aurora B is required for telomere dispersion and disjunction. (right) At the level of telomeres, Aurora promotes in metaphase the delocalization of several telomere/subtelomere components, such as shelterin components (brown), Swi6/HP1 (blue), or cohesin Rad21 (green). At anaphase, Aurora favors the loading of condensin (pink). Our model suggests that the delocalization of telomere components such as the shelterin protein Ccq1 promotes telomere dispersion and Aurora-dependent loading of condensin to chromosome arms.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4362453&req=5

fig9: Model summarizing the different state in telomere clustering throughout mitosis. Schematic representation illustrating the regulation of telomere dissociation throughout mitosis. (left) Telomere foci undergo separation in two discrete steps. Telomere cluster dispersion (up to 6 dots) occurs during metaphase, before chromosome segregation, whereas sister chromatid telomere disjunction (up to 12 dots) is achieved during mid-anaphase. Finally, telomere reclustering occurs during cytokinesis (subsequent G1/S phase). Aurora B is required for telomere dispersion and disjunction. (right) At the level of telomeres, Aurora promotes in metaphase the delocalization of several telomere/subtelomere components, such as shelterin components (brown), Swi6/HP1 (blue), or cohesin Rad21 (green). At anaphase, Aurora favors the loading of condensin (pink). Our model suggests that the delocalization of telomere components such as the shelterin protein Ccq1 promotes telomere dispersion and Aurora-dependent loading of condensin to chromosome arms.
Mentions: Chromosome end protection in S. pombe is similar to that seen in mammals and a recent study has identified several proteins including Pot1 or Ccq1 that form the shelterin complex (Miyoshi et al., 2008). Ccq1 is the S. pombe–specific component of this complex and is required for telomerase recruitment (Moser et al., 2011; Yamazaki et al., 2012). Ccq1 also participates in the telomeric recruitment of a multi-enzyme complex (termed SHREC) that mediates heterochromatic transcriptional gene silencing (Sugiyama et al., 2007). The dissociation of shelterin components from telomeres during mitosis was previously demonstrated using chromatin immunoprecipitation (Chang et al., 2013). Our study provides the timing for this dissociation with respect to chromosome segregation and telomere dispersion. It also suggests that Aurora controls the dissociation of Pot1 or Ccq1 at the metaphase-to-anaphase transition (Fig. 9).

Bottom Line: Dispersion is promoted by the dissociation of Swi6/HP1 and cohesin Rad21 from telomeres, whereas disjunction occurs at anaphase after the phosphorylation of condensin subunit Cnd2.Strikingly, we demonstrate that deletion of Ccq1, a telomeric shelterin component, rescued cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms.Our findings reveal an essential role for telomeres in chromosome arm segregation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de biologie cellulaire et moléculaire du contrôle de la prolifération, Université de Toulouse, F-31062 Toulouse, France Centre National de la Recherche Scientifique, LBCMCP-UMR5088, F-31062 Toulouse, France.

Show MeSH
Related in: MedlinePlus