Centromeres: Old tales and new tools

Vagnarelli, Paola; Ribeiro, Sylvie; Earnshaw, William C.

doi:10.1016/j.febslet.2008.04.014

Cited by 34 publications

(34 citation statements)

References 111 publications

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“…In model 1 (Figure 6B), the kinetochore is built on a chromatin foundation of CENP-A nucleosomes (Palmer and Margolis, 1985;Palmer et al, 1991;Yoda et al, 2000;Black et al, 2007;Dalal et al, 2007;reviewed in Carroll and Straight, 2006;Cheeseman and Desai, 2008;Vagnarelli et al, 2008). In this model, eviction of CENP-A or prevention of its targeting caused by chromatin modifiers would disrupt the foundation for the kinetochore as a primary effect, and the structure would subsequently fall apart.…”

Section: Discussionmentioning

confidence: 99%

“…The centromere/kinetochore is one of the most complex cellular substructures, with more than 80 protein components described to date (reviewed in Carroll and Straight, 2006;Cheeseman and Desai, 2008;Fukagawa, 2008;Vagnarelli et al, 2008). These components perform the complex job of attaching chromosomes to the mitotic spindle; ensuring that those attachments are correct; signaling to delay mitotic progression if they are not, and regulating the movements of the chromosomes toward the spindle poles in anaphase.…”

Section: Introductionmentioning

confidence: 99%

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Hierarchical Inactivation of a Synthetic Human Kinetochore by a Chromatin Modifier

Cardinale

Bergmann

Kelly

et al. 2009

MBoC

114

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We previously used a human artificial chromosome (HAC) with a synthetic kinetochore that could be targeted with chromatin modifiers fused to tetracycline repressor to show that targeting of the transcriptional repressor tTS within kinetochore chromatin disrupts kinetochore structure and function. Here we show that the transcriptional corepressor KAP1, a downstream effector of the tTS, can also inactivate the kinetochore. The disruption of kinetochore structure by KAP1 subdomains does not simply result from loss of centromeric CENP-A nucleosomes. Instead it reflects a hierarchical disruption of the outer kinetochore, with CENP-C levels falling before CENP-A levels and, in certain instances, CENP-H being lost more readily than CENP-C. These results suggest that this novel approach to kinetochore dissection may reveal new patterns of protein interactions within the kinetochore. INTRODUCTIONThe centromere/kinetochore is one of the most complex cellular substructures, with more than 80 protein components described to date (reviewed in Carroll and Straight, 2006;Cheeseman and Desai, 2008;Fukagawa, 2008;Vagnarelli et al., 2008). These components perform the complex job of attaching chromosomes to the mitotic spindle; ensuring that those attachments are correct; signaling to delay mitotic progression if they are not, and regulating the movements of the chromosomes toward the spindle poles in anaphase.The kinetochore is assembled at a unique locus on each natural chromosome. However, for organisms with regional centromeres (Pluta et al., 1995), this reflects only a preference¤, and not an absolute requirement for particular DNA sequences. Kinetochores can form on a wide range of singlecopy and repeated DNA sequences, leading to the conclusion that the ultimate determinants of kinetochore assembly are epigenetic. The long-term purpose of our studies is to determine the epigenetic "landscape" that promotes kinetochore assembly and its maintenance during cell divisions.Experiments including yeast genetics, RNA interference (RNAi) studies in mammalian cells, and gene knockout analysis in mouse and chicken DT40 cells have revealed that kinetochores assemble on a foundation of specialized chromatin containing the kinetochore-specific histone H3 variant CENP-A (Earnshaw and Rothfield, 1985). CENP-A is upstream of almost all other known components in the kinetochore assembly pathway. However, that pathway is multiplex, as recent studies in chicken and Drosophila show that inner kinetochore proteins CENP-H and -C are required for normal CENP-A loading or retention (Okada et al., 2006;Goshima et al., 2007;Erhardt et al., 2008).Our work was inspired by an approach first developed a number of years ago in which cloned fragments of human centromeric DNA were used to form human artificial chromosomes (HACs) in HT1080 fibrosarcoma cells (Harrington et al., 1997;Ikeno et al., 1998). Originally, HAC formation was only achieved with regular repeated arrays of ␣-satellite DNA containing CENP-B boxes Ohzeki et al., 2002;Okada et al., 2007)....

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hierarchical Inactivation of a Synthetic Human Kinetochore by a Chromatin Modifier

Cardinale

Bergmann

Kelly

et al. 2009

MBoC

114

View full text Add to dashboard Cite

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“…Centromeric 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.…”

Section: Introductionmentioning

confidence: 99%

Condensin Regulates the Stiffness of Vertebrate Centromeres

Ribeiro

Gatlin

Yang

et al. 2009

MBoC

136

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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“…Centromere regions of chromosomes are required for the attachment of mitotic and meiotic spindle, sister chromatid cohesion and regulation of chromosome segregation during cell division. Moreover, centromeres have several other important cell functions being involved in spatial genome organisation, heterochromatin assembly and chromocenter formation as well as regulation of expression for certain genes (Choo 2001;Watanabe 2004;Vos et al 2006;Vagnarelli et al 2008).…”

Section: Introductionmentioning

confidence: 99%

High-resolution mapping and transcriptional activity analysis of chicken centromere sequences on giant lampbrush chromosomes

2012

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Exploration into morphofunctional organisation of centromere DNA sequences is important for understanding the mechanisms of kinetochore specification and assembly. In-depth epigenetic analysis of DNA fragments associated with centromeric nucleosome proteins has demonstrated unique features of centromere organisation in chicken karyotype: there are both mature centromeres, which comprise chromosome-specific homogeneous arrays of tandem repeats, and recently evolved primitive centromeres, which consist of non-tandemly organised DNA sequences. In this work, we describe the arrangement and transcriptional activity of chicken centromere repeats for Cen1, Cen2, Cen3, Cen4, Cen7, Cen8, and Cen11 and non-repetitive centromere sequences of chromosomes 5, 27, and Z using highly elongated lampbrush chromosomes, which are characteristic of the diplotene stage of oogenesis. The degree of chromatin packaging and fine spatial organisations of tandemly repetitive and non-tandemly repetitive centromeric sequences significantly differ at the lampbrush stage. Using DNA/RNA FISH, we have demonstrated that during the lampbrush stage, DNA sequences are transcribed within the centromere regions of chromosomes that lack centromere-specific tandem repeats. In contrast, chromosome-specific centromeric repeats Cen1, Cen2, Cen3, Cen4, Cen7, Cen8, and Cen11 do not demonstrate any transcriptional activity during the lampbrush stage. In addition, we found that CNM repeat cluster localises adjacent to non-repetitive centromeric sequences in chicken microchromosome 27 indicating that centromere region in this chromosome is repeat-rich. Cross-species FISH allowed localisation of the sequences homologous to centromeric DNA of chicken chromosomes 5 and 27 in centromere regions of quail orthologous chromosomes.

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Centromeres: Old tales and new tools

Cited by 34 publications

References 111 publications

Hierarchical Inactivation of a Synthetic Human Kinetochore by a Chromatin Modifier

Hierarchical Inactivation of a Synthetic Human Kinetochore by a Chromatin Modifier

Condensin Regulates the Stiffness of Vertebrate Centromeres

High-resolution mapping and transcriptional activity analysis of chicken centromere sequences on giant lampbrush chromosomes

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