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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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Deletion of Ccq1 rescues cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms. (A) Schematic representation illustrating the different localization of condensin throughout mitosis. (B) Single cell analysis of ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (C) Single cell analysis of ccq1Δ ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (D) Single cell analysis of ark1-as mis6-rfp cnd1-gfp cdc11-cfp or ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence of Hoechst. (E) Single cell analysis of cnd2-3E ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1. In B, C, and E, the red arrows highlight the presence or absence of condensin localization to chromosome arms.
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fig8: Deletion of Ccq1 rescues cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms. (A) Schematic representation illustrating the different localization of condensin throughout mitosis. (B) Single cell analysis of ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (C) Single cell analysis of ccq1Δ ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (D) Single cell analysis of ark1-as mis6-rfp cnd1-gfp cdc11-cfp or ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence of Hoechst. (E) Single cell analysis of cnd2-3E ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1. In B, C, and E, the red arrows highlight the presence or absence of condensin localization to chromosome arms.

Mentions: In fission yeast, Aurora B–dependent phosphorylation of the kleisin Cnd2 promotes condensin recruitment to chromosomes (Nakazawa et al., 2011; Tada et al., 2011). To clarify how Ccq1 deletion rescued Aurora inhibition, we performed single cell analysis of condensin (cnd1-gfp) recruitment on chromosomes during mitosis in control cells, ccq1Δ cells, and phosphomimetic cnd2-3E mutant. As previously described, condensin colocalizes to several nuclear compartments during mitosis (Nakazawa et al., 2008), including the nucleolus (rDNA) and kinetochores. At anaphase onset, condensin localization switches to chromosome arms (Fig. 8 D, bottom, Hoechst) and the spindle midzone (Fig. 8, B and D). Transient localization of condensin with telomere clusters was also occasionally observed during metaphase (Fig. 8 D). In ccq1Δ cells and cnd2-3E mutant, this mitotic pattern of condensin localization was unchanged (Fig. 8, C and E, top). However, we noted that although Pot1 decreased in mitosis in control and ccq1Δ cells, it remained strongly associated with telomeres in the cnd2-3E mutant.


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)

Deletion of Ccq1 rescues cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms. (A) Schematic representation illustrating the different localization of condensin throughout mitosis. (B) Single cell analysis of ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (C) Single cell analysis of ccq1Δ ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (D) Single cell analysis of ark1-as mis6-rfp cnd1-gfp cdc11-cfp or ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence of Hoechst. (E) Single cell analysis of cnd2-3E ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1. In B, C, and E, the red arrows highlight the presence or absence of condensin localization to chromosome arms.
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fig8: Deletion of Ccq1 rescues cell death after Aurora inhibition by promoting the loading of condensin on chromosome arms. (A) Schematic representation illustrating the different localization of condensin throughout mitosis. (B) Single cell analysis of ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (C) Single cell analysis of ccq1Δ ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1 (Aurora B inhibition). (D) Single cell analysis of ark1-as mis6-rfp cnd1-gfp cdc11-cfp or ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence of Hoechst. (E) Single cell analysis of cnd2-3E ark1-as pot1-rfp cnd1-gfp cdc11-cfp cells imaged in the presence or absence of 10 µM Napp1. In B, C, and E, the red arrows highlight the presence or absence of condensin localization to chromosome arms.
Mentions: In fission yeast, Aurora B–dependent phosphorylation of the kleisin Cnd2 promotes condensin recruitment to chromosomes (Nakazawa et al., 2011; Tada et al., 2011). To clarify how Ccq1 deletion rescued Aurora inhibition, we performed single cell analysis of condensin (cnd1-gfp) recruitment on chromosomes during mitosis in control cells, ccq1Δ cells, and phosphomimetic cnd2-3E mutant. As previously described, condensin colocalizes to several nuclear compartments during mitosis (Nakazawa et al., 2008), including the nucleolus (rDNA) and kinetochores. At anaphase onset, condensin localization switches to chromosome arms (Fig. 8 D, bottom, Hoechst) and the spindle midzone (Fig. 8, B and D). Transient localization of condensin with telomere clusters was also occasionally observed during metaphase (Fig. 8 D). In ccq1Δ cells and cnd2-3E mutant, this mitotic pattern of condensin localization was unchanged (Fig. 8, C and E, top). However, we noted that although Pot1 decreased in mitosis in control and ccq1Δ cells, it remained strongly associated with telomeres in the cnd2-3E mutant.

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.

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Related in: MedlinePlus