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Chromatin dynamics during the cell cycle at centromeres

Epigenetic : new publication in Nature Reviews Genetic. The team Chromatin dynamics (CNRS/Institut Curie) highlight highlight centromeric chromatin dynamics during the different phases of the cell cycle.

Centromeric chromatin dynamics during the cell cycle. Chromatin undergoes major changes during the cell cycle, which can be visualized by microscopy. Here, chromatin of mouse 3T3 cells is shown83. a | During mitosis, chromatin undergoes compaction with distinct staining patterns in prophase (distinct regions corresponding to chromosomes appear under 4ʹ,6‑diamidino‑2‑phenylindole (DAPI) staining), metaphase (chromosome pairs are clearly visible) and anaphase (chromosome separation to the new daughter cells with single chromosome arms is visible). White boxes highlight a single chromosome in metaphase and anaphase, respectively. Below the metaphase DAPI image is an immunofluorescence image of metaphase chromosomes: the long chromosome arm in blue was stained with DAPI, major satellite DNA was labelled with a fluorescence in situ hybridization (FISH) probe and coloured in green (corresponding to pericentric heterochromatin (PHC)) and the minor satellite DNA was labelled with another FISH probe coloured in red (corresponding to centromeres). This organization is shown diagrammatically on the right. b | During interphase, DNA (stained by DAPI) shows DAPI-dense regions corresponding to chromocentres, which constitute heterochromatin. c | During S phase, DNA is replicated. PHC is replicated in mid S phase and centromeric chromatin in late S phase. Bromodeoxyuridine (BrdU) shows distinct patterns in mid and late S phase, and replication timing was determined by colocalization of BrdU with fluorescent major or minor satellite probes in mouse 3T3 cells83 (scale bars represent 5 μm). Adapted with permission from REF. 83, © Guenatri, M. et al., 2004. Originally published in J. Cell Biol. http://dx.doi.org/10.1083/jcb.200403109.
Centromeric chromatin dynamics during the cell cycle. Chromatin undergoes major changes during the cell cycle, which can be visualized by microscopy. Here, chromatin of mouse 3T3 cells is shown83. a | During mitosis, chromatin undergoes compaction with distinct staining patterns in prophase (distinct regions corresponding to chromosomes appear under 4ʹ,6‑diamidino‑2‑phenylindole (DAPI) staining), metaphase (chromosome pairs are clearly visible) and anaphase (chromosome separation to the new daughter cells with single chromosome arms is visible). White boxes highlight a single chromosome in metaphase and anaphase, respectively. Below the metaphase DAPI image is an immunofluorescence image of metaphase chromosomes: the long chromosome arm in blue was stained with DAPI, major satellite DNA was labelled with a fluorescence in situ hybridization (FISH) probe and coloured in green (corresponding to pericentric heterochromatin (PHC)) and the minor satellite DNA was labelled with another FISH probe coloured in red (corresponding to centromeres). This organization is shown diagrammatically on the right. b | During interphase, DNA (stained by DAPI) shows DAPI-dense regions corresponding to chromocentres, which constitute heterochromatin. c | During S phase, DNA is replicated. PHC is replicated in mid S phase and centromeric chromatin in late S phase. Bromodeoxyuridine (BrdU) shows distinct patterns in mid and late S phase, and replication timing was determined by colocalization of BrdU with fluorescent major or minor satellite probes in mouse 3T3 cells83 (scale bars represent 5 μm). Adapted with permission from REF. 83, © Guenatri, M. et al., 2004. Originally published in J. Cell Biol. http://dx.doi.org/10.1083/jcb.200403109.

“Centromeric chromatin undergoes major changes in composition and architecture during each cell cycle. These changes in specialized chromatin facilitate kinetochore formation in mitosis to ensure proper chromosome segregation. Thus, proper orchestration of centromeric chromatin dynamics during interphase, including replication in S phase, is crucial. We provide the current view concerning the centromeric architecture associated with satellite repeat sequences in mammals and its dynamics during the cell cycle. We summarize the contributions of deposited histone variants and their chaperones, other centromeric components — including proteins and their post-translational modifications, and RNAs — and we link the expression and deposition timing of each component during the cell cycle. Because neocentromeres occur at ectopic sites, we highlight how cell cycle processes can go wrong, leading to neocentromere formation and potentially disease.”

Chromatin dynamics during the cell cycle at centromeres
Sebastian Müller & Geneviève Almouzni / Nature Reviews Genetics (2017) / doi:10.1038/nrg.2016.157