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Stable morphology, but dynamic internal reorganisation, of interphase human chromosomes in living cells.

Müller I, Boyle S, Singer RH, Bickmore WA, Chubb JR - PLoS ONE (2010)

Bottom Line: This contrasted with the behaviour of specific loci on labelled chromosomes, which showed more progressive reorganisation, and revealed that "looping out" of chromatin from chromosome territories is a dynamic state.Chromosome structure showed tremendous resistance to inhibitors of transcription, histone deacetylation and chromatin remodelling.Together, these data indicate steric constraints determine structure, rather than innate chromosome architecture or function-driven anchoring, with interphase chromatin organisation governed primarily by opposition between needs for decondensation and the space available for this to happen.

View Article: PubMed Central - PubMed

Affiliation: Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee, UK.

ABSTRACT
Despite the distinctive structure of mitotic chromosomes, it has not been possible to visualise individual chromosomes in living interphase cells, where chromosomes spend over 90% of their time. Studies of interphase chromosome structure and dynamics use fluorescence in-situ hybridisation (FISH) on fixed cells, which potentially damages structure and loses dynamic information. We have developed a new methodology, involving photoactivation of labelled histone H3 at mitosis, to visualise individual and specific human chromosomes in living interphase cells. Our data revealed bulk chromosome volume and morphology are established rapidly after mitosis, changing only incrementally after the first hour of G1. This contrasted with the behaviour of specific loci on labelled chromosomes, which showed more progressive reorganisation, and revealed that "looping out" of chromatin from chromosome territories is a dynamic state. We measured considerable heterogeneity in chromosome decondensation, even between sister chromatids, which may reflect local structural impediments to decondensation and could potentially amplify transcriptional noise. Chromosome structure showed tremendous resistance to inhibitors of transcription, histone deacetylation and chromatin remodelling. Together, these data indicate steric constraints determine structure, rather than innate chromosome architecture or function-driven anchoring, with interphase chromatin organisation governed primarily by opposition between needs for decondensation and the space available for this to happen.

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Chromosome volume and morphology are defined within the first hour after mitosis.A) Decondensation of a single mitotic chromosome (upper left, bar 5 µm) into two daughter nuclei in interphase (1, 2.5 and 4 hours after mitosis, bar 10 µm). Images are maximal projections of 3D stacks. B–E) Box plots showing changes of volume (µm3) (B), surface area (µm2) (C), sphericity (D) and longest axis (µm) (E) of chromosomes at mitosis and 1 h, 2.5 h and 4 h into interphase. All data sampled from the same movies, of 6 mitotic chromosomes and their 12 interphase descendents.
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pone-0011560-g003: Chromosome volume and morphology are defined within the first hour after mitosis.A) Decondensation of a single mitotic chromosome (upper left, bar 5 µm) into two daughter nuclei in interphase (1, 2.5 and 4 hours after mitosis, bar 10 µm). Images are maximal projections of 3D stacks. B–E) Box plots showing changes of volume (µm3) (B), surface area (µm2) (C), sphericity (D) and longest axis (µm) (E) of chromosomes at mitosis and 1 h, 2.5 h and 4 h into interphase. All data sampled from the same movies, of 6 mitotic chromosomes and their 12 interphase descendents.

Mentions: Little is known about how interphase organisation of chromosome architecture is established in the cell cycle. We therefore analysed the dynamic morphological behaviour of single activated chromosomes at 1, 2.5 and 4 hours after the completion of mitosis (Figure 3A).


Stable morphology, but dynamic internal reorganisation, of interphase human chromosomes in living cells.

Müller I, Boyle S, Singer RH, Bickmore WA, Chubb JR - PLoS ONE (2010)

Chromosome volume and morphology are defined within the first hour after mitosis.A) Decondensation of a single mitotic chromosome (upper left, bar 5 µm) into two daughter nuclei in interphase (1, 2.5 and 4 hours after mitosis, bar 10 µm). Images are maximal projections of 3D stacks. B–E) Box plots showing changes of volume (µm3) (B), surface area (µm2) (C), sphericity (D) and longest axis (µm) (E) of chromosomes at mitosis and 1 h, 2.5 h and 4 h into interphase. All data sampled from the same movies, of 6 mitotic chromosomes and their 12 interphase descendents.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2903487&req=5

pone-0011560-g003: Chromosome volume and morphology are defined within the first hour after mitosis.A) Decondensation of a single mitotic chromosome (upper left, bar 5 µm) into two daughter nuclei in interphase (1, 2.5 and 4 hours after mitosis, bar 10 µm). Images are maximal projections of 3D stacks. B–E) Box plots showing changes of volume (µm3) (B), surface area (µm2) (C), sphericity (D) and longest axis (µm) (E) of chromosomes at mitosis and 1 h, 2.5 h and 4 h into interphase. All data sampled from the same movies, of 6 mitotic chromosomes and their 12 interphase descendents.
Mentions: Little is known about how interphase organisation of chromosome architecture is established in the cell cycle. We therefore analysed the dynamic morphological behaviour of single activated chromosomes at 1, 2.5 and 4 hours after the completion of mitosis (Figure 3A).

Bottom Line: This contrasted with the behaviour of specific loci on labelled chromosomes, which showed more progressive reorganisation, and revealed that "looping out" of chromatin from chromosome territories is a dynamic state.Chromosome structure showed tremendous resistance to inhibitors of transcription, histone deacetylation and chromatin remodelling.Together, these data indicate steric constraints determine structure, rather than innate chromosome architecture or function-driven anchoring, with interphase chromatin organisation governed primarily by opposition between needs for decondensation and the space available for this to happen.

View Article: PubMed Central - PubMed

Affiliation: Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee, UK.

ABSTRACT
Despite the distinctive structure of mitotic chromosomes, it has not been possible to visualise individual chromosomes in living interphase cells, where chromosomes spend over 90% of their time. Studies of interphase chromosome structure and dynamics use fluorescence in-situ hybridisation (FISH) on fixed cells, which potentially damages structure and loses dynamic information. We have developed a new methodology, involving photoactivation of labelled histone H3 at mitosis, to visualise individual and specific human chromosomes in living interphase cells. Our data revealed bulk chromosome volume and morphology are established rapidly after mitosis, changing only incrementally after the first hour of G1. This contrasted with the behaviour of specific loci on labelled chromosomes, which showed more progressive reorganisation, and revealed that "looping out" of chromatin from chromosome territories is a dynamic state. We measured considerable heterogeneity in chromosome decondensation, even between sister chromatids, which may reflect local structural impediments to decondensation and could potentially amplify transcriptional noise. Chromosome structure showed tremendous resistance to inhibitors of transcription, histone deacetylation and chromatin remodelling. Together, these data indicate steric constraints determine structure, rather than innate chromosome architecture or function-driven anchoring, with interphase chromatin organisation governed primarily by opposition between needs for decondensation and the space available for this to happen.

Show MeSH
Related in: MedlinePlus