Chromatin Assembly at Kinetochores Is Uncoupled from DNA Replication

Shelby, Richard D.; Monier, Karine; Sullivan, Kevin F.

doi:10.1083/jcb.151.5.1113

Cited by 224 publications

(227 citation statements)

References 32 publications

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“…It will therefore be critical to determine the histone/nonhistone components associated with budding yeast CenH3 by examining their localization to the CEN at precise cell cycle intervals. Such an experiment is also particularly noteworthy in light of several groups reporting the deposition of CenH3 outside of S phase (42,(46)(47)(48), a detail that has not been observed in budding yeast (19,49). Because of the ability to achieve single-nucleosome resolution, utilization of our modified ChIP protocol should clarify the protein content of the centromeric nucleosome.…”

Section: Discussionmentioning

confidence: 99%

Centromere identity is specified by a single centromeric nucleosome in budding yeast

Furuyama

Biggins

2007

Proc. Natl. Acad. Sci. U.S.A.

240

216

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Chromosome segregation ensures that DNA is equally divided between daughter cells during each round of cell division. The centromere (CEN) is the specific locus on each chromosome that directs formation of the kinetochore, the multiprotein complex that interacts with the spindle microtubules to promote proper chromosomal alignment and segregation during mitosis. CENs are organized into a specialized chromatin structure due to the incorporation of an essential CEN-specific histone H3 variant ( CenH3 ͉ chromatin ͉ kinetochore C hromosome segregation is directed by the multiprotein kinetochore (KT) complex that assembles on centromeres (CENs) and interacts with the spindle apparatus to control chromosome movement during cell division (for reviews, see refs. 1 and 2). Although KT function is conserved, phylogenetic analysis of centromeric DNA reveals no common sequence element that would identify a CEN across species. Like all other parts of the genome, the DNA of CENs is organized into chromatin, a higher order structure in which DNA is wrapped around histones to generate nucleosomes. Typical octameric nucleosomes contain two molecules of each of four histones, H2A, H2B, H3, and H4, whereas centromeric nucleosomes are structurally distinct, containing an evolutionarily conserved CEN-specific histone H3 variant (CenH3) in place of canonical H3 (for review, see ref.3). The conservation of CenH3 across eukaryotes and its strict CEN localization in all species suggest that it is the epigenetic CEN identifier. Consistent with this finding, overexpression of the Drosophila CenH3 leads to its localization in euchromatin and the formation of ectopic KTs, resulting in subsequent defects in genomic stability (4).Despite the requirement for CenH3 in CEN specification, it is unclear how CenH3 nucleosomes structurally organize centromeric DNA to promote KT formation. In humans, CenH3 associates with centromeric ␣ satellite repeats (5), resulting in megabase expanses of centromeric nucleosomes. These centromeric nucleosomes drive the assembly of the KT structure that interacts with multiple microtubules. However, the number of CenH3 nucleosomes far exceeds the number of microtubules associated with a CEN, making the minimal number and arrangement of CenH3 nucleosomes necessary to assemble a single functional KT unclear. In flies and humans, blocks of CenH3 nucleosomes are interspersed with blocks of H3 nucleosomes (6), suggesting that higher order folding of the centromeric

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Section: Discussionmentioning

confidence: 99%

Centromere identity is specified by a single centromeric nucleosome in budding yeast

Furuyama

Biggins

2007

Proc. Natl. Acad. Sci. U.S.A.

240

216

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“…In contrast, it has been shown that CENP-A assembly is uncoupled from DNA replication. Although the peak of endogenous CENP-A assembly probably occurs during G2, epitope-tagged CENP-A can be assembled throughout the chromatin, and at any time during the cell cycle [7].…”

Section: Introductionmentioning

confidence: 99%

Xenopus CENP-A assembly into chromatin requires base excision repair proteins

Zeitlin

Patel

Kavli³

et al. 2005

DNA Repair

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CENP-A is an essential histone H3 variant found in all eukaryotes examined to date. To begin to determine how CENP-A is assembled into chromatin, we developed a binding assay using sperm chromatin in cell-free extract derived from Xenopus eggs. Our data suggest that the catalytic activities of an unidentified deoxycytidine deaminase and UNG2, a uracil DNA glycosylase, are involved in CENP-A assembly. In support of this model, inhibiting deoxycytidine deaminase with zebularine, or uracil DNA glycosylase with Ugi, uracil or UTP results in a lack of detectable CENP-A on sperm DNA.Conversely, inducing DNA damage increases the level of CENP-A detected on sperm chromatin. Our data suggest that base excision repair may be involved in assembly of this histone H3 variant.3

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“…In human cells, centromere DNA replicates in late S phase, and CENP-A is synthesized in G 2 (31). In Drosophila melanogaster, different procedures used to study centromere replication indicated that it occurs either at early or late S phase (1,34).…”

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confidence: 99%

Centromeric Histone H3 Is Essential for Vegetative Cell Division and for DNA Elimination during Conjugation in Tetrahymena thermophila

Cui

Gorovsky

2006

Molecular and Cellular Biology

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The Tetrahymena thermophila CNA1 gene encodes the centromeric H3, Cna1p. Green fluorescent protein (GFP)-tagged Cna1p localizes in micronuclei in dots whose number and behavior during mitosis and conjugation are consistent with centromeres. During interphase, Cna1p-GFP localizes in peripheral dots, suggesting centromeres are associated with the nuclear envelope. Newly synthesized Cna1p-GFP enters micronuclei in mitosis and accumulates in the nucleoplasm. Its deposition at centromeres starts at early S phase and continues through most of S phase. CNA1 is required for vegetative cell growth. Knockdown of CNA1 genes in the somatic macronucleus results in micronuclear DNA loss and delayed chromosome segregation during mitosis. During conjugation, Cna1p-GFP disappears from the centromeres in the developing macronucleus, consistent with centromeric sequences being internal eliminated sequences. Surprisingly, zygotic CNA1 is required for efficient elimination of germ line-specific sequences during development of the new macronuclei but not for the RNA interference pathway, through which sequences are targeted for elimination. Zygotically expressed Cna1p localizes in the spherical structures in which the later stages of DNA elimination occur, and these structures cannot be formed in the absence of zygotic CNA1, suggesting that, in addition to functioning in centromeres, Cna1p may also play a role in organizing the formation of the DNA elimination structures.

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Chromatin Assembly at Kinetochores Is Uncoupled from DNA Replication

Cited by 224 publications

References 32 publications

Centromere identity is specified by a single centromeric nucleosome in budding yeast

Centromere identity is specified by a single centromeric nucleosome in budding yeast

Xenopus CENP-A assembly into chromatin requires base excision repair proteins

Centromeric Histone H3 Is Essential for Vegetative Cell Division and for DNA Elimination during Conjugation in Tetrahymena thermophila

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