Evidence of a differential organization of chromatin containing terminal or interstitial (TTAGGG)&lt;sub&gt;n&lt;/sub&gt; repeats by in situ digestion with nucleases

Fernández, José Luis Fernández; Goyanes, Vicente; Ramiro-Díaz, J.; Gosálvez, Jaime

doi:10.1159/000015098

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…The REs induce structural alterations in metaphase chromosomes which could be related, at the cytological level, to specific structural characteristics of eukaryote chromosome bands, reflecting a distribution of different DNA sequences along the chromosomes (Fernandez et al, 1998;Garcia et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

In situ hybridization of bat chromosomes with human (TTAGGG)n probe, after previous digestion with Alu I

Faria

Morielle‐Versute

2002

Genet. Mol. Biol.

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The purpose of this work was to verify the ability of the enzyme Alu I to cleave and/or remove satellite DNA sequences from heterochromatic regions in chromosomes of bats, by identifying the occurrence of modifications in the pattern of fluorescence in situ hybridization with telomeric DNA. The localization and fluorescence intensity of the telomeric DNA sites of the Alu-digested and undigested chromosomes of species Eumops glaucinus, Carollia perspicillata, and Platyrrhinus lineatus were analyzed. Telomeric sequences were detected at the termini of chromosomes of all three species, although, in C. perspicillata, the signals were very faint or absent in most chromosomes. This finding was interpreted as being due to a reduced number of copies of the telomeric repeat, resulting from extensive telomeric association and/or rearrangements undergone by the chromosomes of Carollia. Fluorescent signals were also observed in centromeric and pericentromeric regions in several two-arm chromosomes of E. glaucinus and C. perspicillata. In E. glaucinus and P. lineatus, some interstitial and terminal telomeric sites were observed to be in association with regions of constitutive heterochromatin and ribosomal DNA (NORs). After digestion, these telomeric sites showed a significant decrease in signal intensity, indicating that enzyme Alu I cleaves and/or removes part of the satellite DNA present in these regions. These results suggest that the telomeric sequence is a component of the heterochromatin, and that the C-band-positive regions of bat chromosomes have a different DNA composition.

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Section: Introductionmentioning

confidence: 99%

In situ hybridization of bat chromosomes with human (TTAGGG)n probe, after previous digestion with Alu I

Faria

Morielle‐Versute

2002

Genet. Mol. Biol.

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“…When a critical size is reached, shortened telomeres promote the formation of telomeric associations (TAS) generating dicentrics, ring chromosomes or chromatid fusions encountered in chromosome instability. Furthermore, due to their G-rich sequence (Brahmachari et al, 1995) or the peculiar conformation of the chromatin (Tommerup et al, 1994;Fernandez et al, 1998), telomeres may also promote recombination (Pluta and Zakian, 1989).…”

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confidence: 99%

The influence of interstitial telomeric sequences on chromosome instability in human cells

Desmaze

Alberti²,

Martins³

et al. 1999

Cytogenet Genome Res

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Although most telomere repeat sequences are found at the ends of chromosomes, some telomeric repeat sequences are also found at intrachromosomal locations in mammalian cells. Several studies have found that these interstitial telomeric repeat sequences can promote chromosome instability in rodent cells, either spontaneously or following ionizing radiation. In the present study we describe the extensive cytogenetic analysis of three different human cell lines with plasmids containing telomeric repeat sequences integrated at interstitial sites. In two of these cell lines, Q18 and P8SX, instability has been detected in the chromosome containing the integrated plasmid, involving breakage/fusion/bridge cycles or amplification of the plasmid DNA, respectively. However, the data suggest that the instability observed is characteristic of the general instability in these cell lines and that the telomeric repeat sequences themselves are not responsible. Consistent with this interpretation, the chromosome containing an integrated plasmid with 500 bp of telomeric repeat sequences is highly stable in the third cell line, SNG28, which has a relatively stable genome. The stability of the chromosome containing the integrated plasmid sequences in SNG28 makes this an excellent cell line to study the effect of ionizing radiation on the stability of interstitial telomeric sequences in human cells.

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“…Human lymphocyte cultures were constructed as described in Fernández et al (1998). Male and female PCR products were labelled with digoxigenin-dUTP, resuspended to a final concentration of 1 ng/µL in hybridization solution containing 50% formamide, and in situ hybridized to standard metaphase chromosome spreads of both sexes.…”

Section: Fluorescence In Situ Hybridization (Fish)mentioning

confidence: 99%

A PCR product derived from female DNA with regional localization on the Y chromosome

Torre

Martínez-Ramírez²,

Fernández³

et al. 2000

Genome

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A 154-bp PCR product amplified from human female DNA mapped onto the Y chromosome under high-stringency in situ hybridization conditions. The female DNA sequence revealed an 89% homology with the HSDYZ1 sequence. When the same primers were used to amplify male DNA, a 154-bp DNA fragment was also obtained, showing a 98% homology with HSDYZ1. However, although the HSDYZ1 sequence is widely distributed along the long arm of the Y chromosome, both of these particular PCR products are di-regionally localized within this distal block of constitutive heterochromatin. In situ hybridization under lower stringency showed that these 154-bp sequences map both onto the autosomes and the Y chromosome. Overall, this paper shows (i) a new class of DNA sequences shared by the autosomes and the Y chromosome; and (ii) a substructured organization of some DNA repeats within the DYZ1 family that forms a large part of the constitutive heterochromatin of the Y chromosome.

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Evidence of a differential organization of chromatin containing terminal or interstitial (TTAGGG)<sub>n</sub> repeats by in situ digestion with nucleases

Cited by 9 publications

References 15 publications

In situ hybridization of bat chromosomes with human (TTAGGG)n probe, after previous digestion with Alu I

In situ hybridization of bat chromosomes with human (TTAGGG)n probe, after previous digestion with Alu I

The influence of interstitial telomeric sequences on chromosome instability in human cells

A PCR product derived from female DNA with regional localization on the Y chromosome

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