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Boyarchuk E, Filipescu D, Vassias I, Cantaloube S, Almouzni G. The histone variant composition of centromeres is controlled by the pericentric heterochromatin state during the cell cycle. J Cell Sci 2014; 127:3347-59. [PMID: 24906798 DOI: 10.1242/jcs.148189] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Correct chromosome segregation requires a unique chromatin environment at centromeres and in their vicinity. Here, we address how the deposition of canonical H2A and H2A.Z histone variants is controlled at pericentric heterochromatin (PHC). Whereas in euchromatin newly synthesized H2A and H2A.Z are deposited throughout the cell cycle, we reveal two discrete waves of deposition at PHC - during mid to late S phase in a replication-dependent manner for H2A and during G1 phase for H2A.Z. This G1 cell cycle restriction is lost when heterochromatin features are altered, leading to the accumulation of H2A.Z at the domain. Interestingly, compromising PHC integrity also impacts upon neighboring centric chromatin, increasing the amount of centromeric CENP-A without changing the timing of its deposition. We conclude that the higher-order chromatin structure at the pericentric domain influences dynamics at the nucleosomal level within centromeric chromatin. The two different modes of rearrangement of the PHC during the cell cycle provide distinct opportunities to replenish one or the other H2A variant, highlighting PHC integrity as a potential signal to regulate the deposition timing and stoichiometry of histone variants at the centromere.
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Affiliation(s)
- Ekaterina Boyarchuk
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Dan Filipescu
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Isabelle Vassias
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Sylvain Cantaloube
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
| | - Geneviève Almouzni
- Institut Curie, Centre de Recherche, Paris, 75248 France CNRS, UMR3664, Paris, 75248 France Equipe Labellisée Ligue contre le Cancer, UMR3664, Paris, 75248 France UPMC, UMR3664, Paris, 75248 France Sorbonne University, PSL, 75006 Paris, France
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Papait R, Pistore C, Negri D, Pecoraro D, Cantarini L, Bonapace IM. Np95 is implicated in pericentromeric heterochromatin replication and in major satellite silencing. Mol Biol Cell 2006; 18:1098-106. [PMID: 17182844 PMCID: PMC1805105 DOI: 10.1091/mbc.e06-09-0874] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Heterochromatin plays an important role in transcriptional repression, for the correct segregation of chromosomes and in the maintenance of genome stability. Pericentric heterochromatin (PH) replication and formation have been proposed to occur in the pericentric heterochromatin duplication body (pHDB). A central question is how the underacetylated state of heterochromatic histone H4 tail is established and controlled, because it is a key event during PH replication and is essential to maintain the compacted and silenced state of these regions. Np95 is a cell cycle regulated and is a nuclear histone-binding protein that also recruits HDAC-1 to target promoters. It is essential for S phase and for embryonic formation and is implicated in chromosome stability. Here we show that Np95 is part of the pHDB, and its functional ablation causes a strong reduction in PH replication. Depletion of Np95 also causes a hyperacetylation of lysines 8, 12, and 16 of heterochromatin histone H4 and an increase of pericentromeric major satellite transcription, whose RNAs are key players for heterochromatin formation. We propose that Np95 is a new relevant protein involved in heterochromatin replication and formation.
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Affiliation(s)
- Roberto Papait
- Department of Structural and Functional Biology, University of Insubria, 21052 Busto Arsizio (VA), Italy
| | - Christian Pistore
- Department of Structural and Functional Biology, University of Insubria, 21052 Busto Arsizio (VA), Italy
| | - Diego Negri
- Department of Structural and Functional Biology, University of Insubria, 21052 Busto Arsizio (VA), Italy
| | - Daniela Pecoraro
- Department of Structural and Functional Biology, University of Insubria, 21052 Busto Arsizio (VA), Italy
| | - Lisa Cantarini
- Department of Structural and Functional Biology, University of Insubria, 21052 Busto Arsizio (VA), Italy
| | - Ian Marc Bonapace
- Department of Structural and Functional Biology, University of Insubria, 21052 Busto Arsizio (VA), Italy
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Shimizu N, Shingaki K. Macroscopic folding and replication of the homogeneously staining region in late S phase leads to the appearance of replication bands in mitotic chromosomes. J Cell Sci 2004; 117:5303-12. [PMID: 15454579 DOI: 10.1242/jcs.01414] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chromosomal G/R bands are alternating domains differing in their nucleotide sequence biases. The bands are also related to the time of replication: pulse-labeling during S phase makes the replication sites as visible as replication bands that are close to the G/R bands in mitotic chromosomes. We previously showed that a plasmid bearing a mammalian replication origin efficiently generated a chromosomal homogeneously staining region (HSR). Here, we analyze the replication of this artificial HSR and show that it was replicated at the last stage of S phase. The HSR was composed of plasmid repeats only; nonetheless, we found that replication sites pulse-labeled during late S phase appeared as bands in the mitotic HSR and their number was dependent on the length of the HSR. Therefore, replication bands might not arise from sequence information per se. To understand the chronological order of appearance of replication sites, we performed a double pulse-chase experiment using IdU and CldU. Replication of the entire HSR required 100-120 minutes. During this period, the replicated sites appeared as bands at the first and last stages, but in between were apparently scattered along the entire HSR. An analysis of S-phase nuclei revealed that the replication started at the periphery of the globular HSR domain, followed by initiation in the internal domain. The replicated HSR appeared as a ring or a pair of extended spirals in late G2-phase nuclei. To account for these findings, we present a model in which the HSR is folded as a coiled-coil structure that is replicated from the outside to the inside in S phase nuclei.
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Affiliation(s)
- Noriaki Shimizu
- Faculty of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-hiroshima, 739-8521, Japan.
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Guenatri M, Bailly D, Maison C, Almouzni G. Mouse centric and pericentric satellite repeats form distinct functional heterochromatin. ACTA ACUST UNITED AC 2004; 166:493-505. [PMID: 15302854 PMCID: PMC2172221 DOI: 10.1083/jcb.200403109] [Citation(s) in RCA: 369] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heterochromatin is thought to play a critical role for centromeric function. However, the respective contributions of the distinct repetitive sequences found in these regions, such as minor and major satellites in the mouse, have remained largely unsolved. We show that these centric and pericentric repeats on the chromosomes have distinct heterochromatic characteristics in the nucleus. Major satellites from different chromosomes form clusters associated with heterochromatin protein 1α, whereas minor satellites are individual entities associated with centromeric proteins. Both regions contain methylated histone H3 (Me-K9 H3) but show different micrococcal nuclease sensitivities. A dinucleosome repeating unit is found specifically associated with major satellites. These domains replicate asynchronously, and chromatid cohesion is sustained for a longer time in major satellites compared with minor satellites. Such prolonged cohesion in major satellites is lost in the absence of Suv39h histone methyltransferases. Thus, we define functionally independent centromeric subdomains, which spatio-temporal isolation is proposed to be important for centromeric cohesion and dissociation during chromosome segregation.
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Affiliation(s)
- Mounia Guenatri
- Institut Curie/Research section, UMR218 du Centre National pour la Recherche Scientifique, 26 rue d'Ulm, 75248 Paris Cedex 05, France
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Jeppesen P. Histone acetylation: a possible mechanism for the inheritance of cell memory at mitosis. Bioessays 1997; 19:67-74. [PMID: 9008418 DOI: 10.1002/bies.950190111] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Immunofluorescent labelling demonstrates that human metaphase chromosomes contain hyperacetylated histone H4. With the exception of the inactive X chromosome in female cells, where the bulk of histone H4 is underacetylated, H4 hyperacetylation is non-uniformly distributed along the chromosomes and clustered in cytologically resolvable chromatin domains that correspond, in general, with the R-bands of conventional staining. The strongest immunolabelling is often found in T-bands, the subset of intense R-bands having the highest GC content. The majority of mapped genes also occurs in R-band regions, with the highest gene density in T-bands. These observations are consistent with a model in which hyperacetylation of histone H4 marks the position of potentially active gene sequences on metaphase chromosomes. Since acetylation is maintained during mitosis, progeny cells receive an imprint of the histone H4 acetylation pattern that was present on the parental chromosomes before cell division. Histone acetylation could provide a mechanism for propagating cell memory, defined as the maintenance of committed states of gene expression through cell lineages.
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Affiliation(s)
- P Jeppesen
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, Scotland, UK
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