The radial arrangement of the human chromosome 7 in the lymphocyte cell nucleus is associated with chromosomal band gene density

Federico, Concetta; Cantarella, Catia Daniela; Mare, Patrizia Di; Tosi, Sabrina; Saccone, Salvatore

doi:10.1007/s00412-008-0160-x

Cited by 39 publications

(75 citation statements)

References 49 publications

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“…This (re)positioning of the derivative chromosomes is consistent with the change in gene density within a 2-Mb window around the breakpoints, which has been shown to be a good predictor of radial chromosome positioning within lymphoblastoid nuclei (Boyle et al 2001;Murmann et al 2005;Federico et al 2008). The transposition of the derivative chromosome 11 to a more central position within the nucleus results in HSA11 genes retained on this chromosome being placed into an anomalous chromatin environment, potentially causing changes in their level of expression.…”

Section: The Derivative Chromosomes Occupy Different Nuclear Positionsupporting

confidence: 49%

The effect of translocation-induced nuclear reorganization on gene expression

Harewood¹,

Schütz²,

Boyle³

et al. 2010

Genome Res.

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Translocations are known to affect the expression of genes at the breakpoints and, in the case of unbalanced translocations, alter the gene copy number. However, a comprehensive understanding of the functional impact of this class of variation is lacking. Here, we have studied the effect of balanced chromosomal rearrangements on gene expression by comparing the transcriptomes of cell lines from controls and individuals with the t(11;22)(q23;q11) translocation. The number of differentially expressed transcripts between translocation-carrying and control cohorts is significantly higher than that observed between control samples alone, suggesting that balanced rearrangements have a greater effect on gene expression than normal variation. Many of the affected genes are located along the length of the derived chromosome 11. We show that this chromosome is concomitantly altered in its spatial organization, occupying a more central position in the nucleus than its nonrearranged counterpart. Derivative 22-mapping chromosome 22 genes, on the other hand, remain in their usual environment. Our results are consistent with recent studies that experimentally altered nuclear organization, and indicated that nuclear position plays a functional role in regulating the expression of some genes in mammalian cells. Our study suggests that chromosomal translocations can result in hitherto unforeseen, large-scale changes in gene expression that are the consequence of alterations in normal chromosome territory positioning. This has consequences for the patterns of gene expression change seen during tumorigenesis-associated genome instability and during the karyotype changes that lead to speciation.

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Section: The Derivative Chromosomes Occupy Different Nuclear Positionsupporting

confidence: 49%

The effect of translocation-induced nuclear reorganization on gene expression

Harewood¹,

Schütz²,

Boyle³

et al. 2010

Genome Res.

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“…relatively higher bars in shell 5). Evidence suggests that extrapolations from 2D data (such as that presented in this study) are an indicator of real 3D positions (Federico et al 2008); however, this data relates to lymphocyte nuclei and it is possible that sample prepreparation can affect nuclear organisation. It would therefore perhaps be unwise to over-interpret these 2D projections and further experiments on preserved 3D sections, perhaps coupled with confocal microscopy and/or deconvolution algorithms could be used to Table 4 The nuclear address for all the loci analysed in each of the OAT males…”

Section: Discussionmentioning

confidence: 75%

Nuclear organisation of sperm remains remarkably unaffected in the presence of defective spermatogenesis

et al. 2011

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Organisation of chromosome territories in interphase nuclei has been studied in many systems and positional alterations have been associated with disease phenotypes (e.g. laminopathies, cancer) in somatic cells. Altered nuclear organisation is also reported in developmental processes such as mammalian spermatogenesis where a "chromocentre" model is proposed with the centromeres and sex chromosomes repositioning to the nuclear centre. The purpose of this study was to test the hypothesis that alterations in nuclear organisation of human spermatozoa are associated with defects upstream in spermatogenesis (as manifest in certain infertility phenotypes). The nuclear address of (peri-) centromeric loci for 18 chromosomes (1-4, 6-12, 15-18, 20, X and Y) was assayed in 20 males using established algorithms for 3D extrapolations of 2D data. The control group comprised 10 fertile sperm donors while the test group was 10 patients with severely compromised semen parameters including high sperm aneuploidy. All loci examined in the control group adopted defined, interior positions thus providing supporting evidence for the presence of a chromocentre and interior sex chromosome territories. In the test group however there were subtle alterations in the nuclear address for certain centromeres in individual patients and, when all patient results were pooled, some different nuclear addresses were observed for chromosomes 3, 6, 12 and 18. Considering the extensive impairment of spermatogenesis in the test group (evidenced by compromised semen parameters and increased chromosome abnormalities), the observed differences in nuclear organisation for centromeric loci compared to the controls were modest. A defined pattern of nuclear reorganisation of centromeric loci in sperm heads therefore appears to be a remarkably robust process, even if spermatogenesis is severely compromised.

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“…On the other hand, HLXB9, that is not transcriptionally active after the developmental stages of embryonic life, is normally localized toward the nuclear periphery. 8 We have shown here that the translocated HLXB9 locus is brought to a more internal position by its translocation partner ETV6 in t(7;12) leukaemic cells, in which the HLXB9 expression is activated.…”

Section: Letters To the Editormentioning

confidence: 97%

“…Using an earlier-described procedure, 8 we localized the HLXB9 gene at the nuclear periphery (see Figure 3, left part), a nuclear compartment largely composed of compact, and generally nonexpressed, chromatin. This peripheral localization was consistent in cells of healthy individuals and in leukaemic cells not harbouring the t(7;12).…”

Section: Letters To the Editormentioning

confidence: 99%