Somatic pairings of the Y heterochromatin in human XYY and XYqi cells

Schmid, Michael; Poppen, A.; Schmid, Werner; Engel, Wolfgang

doi:10.1159/000131571

Cited by 11 publications

(6 citation statements)

References 4 publications

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“…Firstly, the results of statistical analysis of chromosome arrangements at metaphase are compared with the results of chromosome arrangements at interphase obtained with the microbeam or other independent methods (Schmid et al 1981;Dutrillaux et al 1981;Hager et al 1982;Hens et al 1982). The variability of interphase chromosome arrangements as indicated by the present microbeam study is in agreement with the variability of chromosome positions and the lack of association between homologous chromosomes in the metaphase spread.…”

Section: Discussionsupporting

confidence: 75%

“…Recent studies of the distribution of interphasic centromeres indicate considerable variation in cell types from different plant and mammalian species (Church and Moens 1976;Del Fosse and Church 1981;Moroi et al 1981;Brenner et al 1981). Thirdly, and probably most important, the technical procedures routinely used for obtaining well spread metaphases (often including colchicine treatment and hypotonic shock) alter the chromosome arrangement of the intact metaphase plate to an extent which has not been documented by most investigators, although it can be shown that the relationship between chromosome arrangements at interphase and metaphase is critically influenced by the experimental regimen followed (Schmid et al 1981).…”

Section: Discussionmentioning

confidence: 99%

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Analysis of chromosome positions in the interphase nucleus of Chinese hamster cells by laser-UV-microirradiation experiments

et al. 1982

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Summary. Unsynchronized cells of an essentially diploid strain of female Chinese hamster cells derived from lung tissue (CHL) were laser-UV-microirradiated (2 = 257 nm) in the nucleus either at its central part or at its periphery. After 7-9 h postincubation with 0.5 mM caffeine, chromosome preparations were made in situ. Twenty-one and 29 metaphase spreads, respectively, with partial chromosome shattering (PCS) obtained after microirradiation at these two nuclear sites, were Q-banded and analyzed in detail. A positive correlation was observed between the frequency of damage of chromosomes and both their DNA content and length at metaphase. No significant difference was observed between the frequencies of damage obtained for individual chromosomes at either site of microirradiation. The frequency of joint damage of homologous chromosomes was low as compared to nonhomologous ones. Considerable variation was noted in different cells in the combinations of jointly shattered chromosomes. Evidence which justifies an interpretation of these data in terms of an interphase arrangement of chromosome territories is discussed. Our data strongly argue against somatic pairing as a regular event, and suggest a considerable variability of chromosome positions in different nuclei. However, present data do not exclude the possibility of certain non-random chromosomal arrangements in CHL-nuclei. The interphase chromosome distribution revealed by these experiments is compared with centromere-centromere, centromere-center and angle analyses of metaphase spreads and the relationship between interphase and metaphase arrangements of chromosomes is discussed.

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Section: Discussionsupporting

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Analysis of chromosome positions in the interphase nucleus of Chinese hamster cells by laser-UV-microirradiation experiments

et al. 1982

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“…In contrast with the C-bands of chromosome 1, 9 and 16, the noncentric C-band of the Y chromosome is almost unaffected in normal cells on MMC-treatment (Shaw and Cohen, 1965;Morad et al, 1973), despite a comparable size of the C-bands (Joseph et al, 1982b). However, in lymphocytes from a XYY male patient MMC treatment resulted in a frequent involvement of the Y chromosomes in interchanges, almost exclusively in Y-Y configurations (Schmid et al, 1981;Joseph et al, 1982b). Hence it is clear that also the C-band of chromosome Y is susceptible to MMC ICLs, but that sequence homology is required for a subsequent formation of chromosome interchanges.…”

Section: Discussionmentioning

confidence: 99%

Mitomycin C-induced pairing of heterochromatin reflects initiation of DNA repair and chromatid exchange formation

Abdel-Halim

Natarajan

Mullenders

et al. 2005

Journal of Cell Science

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Chromatid interchanges induced by the DNA cross-linking agent mitomycin C (MMC) are over-represented in human chromosomes containing large heterochromatic regions. We found that nearly all exchange breakpoints of chromosome 9 are located within the paracentromeric heterochromatin and over 70% of exchanges involving chromosome 9 are between its homologues. We provide evidence that the required pairing of chromosome 9 heterochromatic regions occurs in G0/G1 and S-phase cells as a result of an active cellular process initiated upon MMC treatment. By contrast, no pairing was observed for a euchromatic paracentromeric region of the equal-sized chromosome 8. The MMC-induced pairing of chromosome 9 heterochromatin is observed in a subset of cells; its percentage closely mimics the frequency of homologous interchanges found at metaphase. Moreover, the absence of pairing in cells derived from XPF patients correlates with an altered spectrum of MMC-induced exchanges. Together, the data suggest that the heterochromatin-specific pairing following MMC treatment reflects the initiation of DNA cross-link repair and the formation of exchanges.

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“…9 in human interphase nuclei can be observed by means of the Giemsa-ll-staining procedure (Gagn6 and Laberge 1972;Spaeter 1975). Another example concerns the position of the heterochromatic sex chromosomes forming large chromocenters in interphase nuclei of Microtus agrestis (Pera and Schwarzacher 1970), while the position of the human Y-heterochromatin can be identified by quinacrine mustard staining (Pearson et ah 1970;Schmid et al 1981).…”

Section: Introductionmentioning

confidence: 99%

Sex chromosome positions in human interphase nuclei as studied by in situ hybridization with chromosome specific DNA probes

et al. 1984

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Summary.Two cloned repetitive DNA probes, pXBR and CY1, which bind preferentially to specific regions of the human X and Y chromosome, respectively, were used to study the distribution of the sex chromosomes in human lymphocyte nuclei by in situ hybridization experiments. Our data indicate a large variability of the distances between the sex chromosomes in male and female interphase nuclei. However, the mean distance observed between the X and Y chromosome was significantly smaller than the mean distance observed between the two X-chromosomes. The distribution of distances determined experimentally is compared with three model distributions of distances, and the question of a non-random distribution of sex chromosomes is discussed. Mathematical details of these model distributions are provided in an Appendix to this paper. In the case of a human translocation chromosome (Xqter---~ Xp22.2: :Yq11--->Yqter) contained in the Chinese hamster x human hybrid cell line 445 x 393, the binding sites of pXBR and CY1 were found close to each other in most interphase nuclei. These data demonstrate the potential use of chromosome-specific repetitive DNA probes to study the problem of interphase chromosome topography.

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Somatic pairings of the Y heterochromatin in human XYY and XYqi cells

Cited by 11 publications

References 4 publications

Analysis of chromosome positions in the interphase nucleus of Chinese hamster cells by laser-UV-microirradiation experiments

Analysis of chromosome positions in the interphase nucleus of Chinese hamster cells by laser-UV-microirradiation experiments

Mitomycin C-induced pairing of heterochromatin reflects initiation of DNA repair and chromatid exchange formation

Sex chromosome positions in human interphase nuclei as studied by in situ hybridization with chromosome specific DNA probes

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