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The three-dimensional organization of telomeres in the nucleus of mammalian cells.

Chuang TC, Moshir S, Garini Y, Chuang AY, Young IT, Vermolen B, van den Doel R, Mougey V, Perrin M, Braun M, Kerr PD, Fest T, Boukamp P, Mai S - BMC Biol. (2004)

Bottom Line: In tumor cells, the 3D telomere organization is distorted and aggregates are formed.The results emphasize a non-random and dynamic 3D nuclear telomeric organization and its importance to genomic stability.Based on our findings, it appears possible to examine telomeric aggregates suggestive of genomic instability in individual interphase nuclei and tissues without the need to examine metaphases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Manitoba Institute of Cell Biology, CancerCare Manitoba, University of Manitoba, 675 McDermot Avenue, Winnipeg, MB, R3E 0V9, Canada. tcychuang@hotmail.com

ABSTRACT

Background: The observation of multiple genetic markers in situ by optical microscopy and their relevance to the study of three-dimensional (3D) chromosomal organization in the nucleus have been greatly developed in the last decade. These methods are important in cancer research because cancer is characterized by multiple alterations that affect the modulation of gene expression and the stability of the genome. It is, therefore, essential to analyze the 3D genome organization of the interphase nucleus in both normal and cancer cells.

Results: We describe a novel approach to study the distribution of all telomeres inside the nucleus of mammalian cells throughout the cell cycle. It is based on 3D telomere fluorescence in situ hybridization followed by quantitative analysis that determines the telomeres' distribution in the nucleus throughout the cell cycle. This method enables us to determine, for the first time, that telomere organization is cell-cycle dependent, with assembly of telomeres into a telomeric disk in the G2 phase. In tumor cells, the 3D telomere organization is distorted and aggregates are formed.

Conclusions: The results emphasize a non-random and dynamic 3D nuclear telomeric organization and its importance to genomic stability. Based on our findings, it appears possible to examine telomeric aggregates suggestive of genomic instability in individual interphase nuclei and tissues without the need to examine metaphases. Such new avenues of monitoring genomic instability could potentially impact on cancer biology, genetics, diagnostic innovations and surveillance of treatment response in medicine.

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Metaphase plate prepared from fetal liver cells directly isolated from day 10 old mouse embryos. Metaphase chromosomes and spreads were prepared as described [30] and hybridized with a PNA-telomeric probe that was Cy3 labelled. More than 90% of the telomeres are clearly observed.
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Figure 4: Metaphase plate prepared from fetal liver cells directly isolated from day 10 old mouse embryos. Metaphase chromosomes and spreads were prepared as described [30] and hybridized with a PNA-telomeric probe that was Cy3 labelled. More than 90% of the telomeres are clearly observed.

Mentions: It is expected that 80 telomeres will be observed in the interphase nucleus for normal mouse cells (92 for a normal somatic human cell), however, in our measurements we were usually able to identify approximately 40 separated telomere regions in each mouse cell (50 in human cells). Similar results have been described before [23,28]. This is probably due to neighbouring telomeres that are closer than the optical resolution (see Fig. 3), but it does not affect the analysis of the telomere distribution in the nucleus as long as the hybridization efficiency is high. This was verified by two-dimensional measurements of all the telomeres in a metaphase spread (using the same probe), where at least 90% of the telomeres are unambiguously observed (Fig. 4).


The three-dimensional organization of telomeres in the nucleus of mammalian cells.

Chuang TC, Moshir S, Garini Y, Chuang AY, Young IT, Vermolen B, van den Doel R, Mougey V, Perrin M, Braun M, Kerr PD, Fest T, Boukamp P, Mai S - BMC Biol. (2004)

Metaphase plate prepared from fetal liver cells directly isolated from day 10 old mouse embryos. Metaphase chromosomes and spreads were prepared as described [30] and hybridized with a PNA-telomeric probe that was Cy3 labelled. More than 90% of the telomeres are clearly observed.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC425602&req=5

Figure 4: Metaphase plate prepared from fetal liver cells directly isolated from day 10 old mouse embryos. Metaphase chromosomes and spreads were prepared as described [30] and hybridized with a PNA-telomeric probe that was Cy3 labelled. More than 90% of the telomeres are clearly observed.
Mentions: It is expected that 80 telomeres will be observed in the interphase nucleus for normal mouse cells (92 for a normal somatic human cell), however, in our measurements we were usually able to identify approximately 40 separated telomere regions in each mouse cell (50 in human cells). Similar results have been described before [23,28]. This is probably due to neighbouring telomeres that are closer than the optical resolution (see Fig. 3), but it does not affect the analysis of the telomere distribution in the nucleus as long as the hybridization efficiency is high. This was verified by two-dimensional measurements of all the telomeres in a metaphase spread (using the same probe), where at least 90% of the telomeres are unambiguously observed (Fig. 4).

Bottom Line: In tumor cells, the 3D telomere organization is distorted and aggregates are formed.The results emphasize a non-random and dynamic 3D nuclear telomeric organization and its importance to genomic stability.Based on our findings, it appears possible to examine telomeric aggregates suggestive of genomic instability in individual interphase nuclei and tissues without the need to examine metaphases.

View Article: PubMed Central - HTML - PubMed

Affiliation: Manitoba Institute of Cell Biology, CancerCare Manitoba, University of Manitoba, 675 McDermot Avenue, Winnipeg, MB, R3E 0V9, Canada. tcychuang@hotmail.com

ABSTRACT

Background: The observation of multiple genetic markers in situ by optical microscopy and their relevance to the study of three-dimensional (3D) chromosomal organization in the nucleus have been greatly developed in the last decade. These methods are important in cancer research because cancer is characterized by multiple alterations that affect the modulation of gene expression and the stability of the genome. It is, therefore, essential to analyze the 3D genome organization of the interphase nucleus in both normal and cancer cells.

Results: We describe a novel approach to study the distribution of all telomeres inside the nucleus of mammalian cells throughout the cell cycle. It is based on 3D telomere fluorescence in situ hybridization followed by quantitative analysis that determines the telomeres' distribution in the nucleus throughout the cell cycle. This method enables us to determine, for the first time, that telomere organization is cell-cycle dependent, with assembly of telomeres into a telomeric disk in the G2 phase. In tumor cells, the 3D telomere organization is distorted and aggregates are formed.

Conclusions: The results emphasize a non-random and dynamic 3D nuclear telomeric organization and its importance to genomic stability. Based on our findings, it appears possible to examine telomeric aggregates suggestive of genomic instability in individual interphase nuclei and tissues without the need to examine metaphases. Such new avenues of monitoring genomic instability could potentially impact on cancer biology, genetics, diagnostic innovations and surveillance of treatment response in medicine.

Show MeSH
Related in: MedlinePlus