Interstitial telomeric repeats-associated DNA breaks

AbstractLinker histones play a pivotal role in shaping chromatin architecture, notably through their globular H1 (GH1) domain that contacts the nucleosome and linker DNA. Yet, the interplay of H1 with chromatin factors along the epigenome landscape is poorly understood. Here, we report that Arabidopsis H1 favors chromatin compaction and H3K27me3 marking on a majority of Polycomb-targeted protein-coding genes while preventing H3K27me3 accumulation on telomeres and pericentromeric interstitial telomeric repeats (ITRs). These contrasting effects of H1 on H3K27me3 enrichment are associated with long-distance effects on the 3D organization of telomeres and ITRs. Mechanistically, H1 prevents ITRs from being invaded by Telomere Repeat Binding 1 (TRB1), a GH1-containing telomere component with an extra-telomeric function in targeting Polycomb to genes bearing telomeric motifs. We propose that reciprocal DNA binding of H1 and TRB1 to clustered telobox motifs prevents H3K27me3 accumulation on large chromosomal blocks, conferring a sequence-specific role to H1 in epigenome homeostasis.

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Combinatorial genomic data refute the human chromosome 2 evolutionary fusion and build a model of functional design for interstitial telomeric repeats

The Proceedings of the International Conference on Creationism ◽

10.15385/jpicc.2018.8.1.22 ◽

2018 ◽

Vol 8 (1) ◽

pp. 222-228

Author(s):

Jeffrey Tomkins

Keyword(s):

Human Chromosome ◽

Genomic Data ◽

Chromosome 2 ◽

Functional Design ◽

Telomeric Repeats ◽

Interstitial Telomeric Repeats

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Interstitial telomeric repeats are not preferentially involved in radiation-induced chromosome aberrations in human cells

Cytogenetic and Genome Research ◽

10.1159/000077476 ◽

2004 ◽

Vol 104 (1-4) ◽

pp. 123-130 ◽

Cited By ~ 12

Author(s):

C. Desmaze ◽

L.M. Pirzio ◽

R. Blaise ◽

C. Mondello ◽

E. Giulotto ◽

...

Keyword(s):

Chromosome Aberrations ◽

Human Cells ◽

Telomeric Repeats ◽

Radiation Induced ◽

Interstitial Telomeric Repeats

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Cytogenetic Analysis Did Not Reveal Differentiated Sex Chromosomes in Ten Species of Boas and Pythons (Reptilia: Serpentes)

Genes ◽

10.3390/genes10110934 ◽

2019 ◽

Vol 10 (11) ◽

pp. 934 ◽

Cited By ~ 4

Author(s):

Augstenová ◽

Mazzoleni ◽

Kostmann ◽

Altmanová ◽

Frynta ◽

...

Keyword(s):

In Situ Hybridization ◽

Sex Chromosomes ◽

Chromosomal Rearrangements ◽

Telomeric Repeats ◽

Molecular Cytogenetic ◽

Poorly Differentiated ◽

Python Bivittatus ◽

Interstitial Telomeric Repeats ◽

Cytogenetic Methods

Homologous and differentiated ZZ/ZW sex chromosomes (or derived multiple neo-sex chromosomes) were often described in caenophidian snakes, but sex chromosomes were unknown until recently in non-caenophidian snakes. Previous studies revealed that two species of boas (Boa imperator, B. constrictor) and one species of python (Python bivittatus) independently evolved XX/XY sex chromosomes. In addition, heteromorphic ZZ/ZW sex chromosomes were recently revealed in the Madagascar boa (Acrantophis sp. cf. dumerili) and putatively also in the blind snake Myriopholis macrorhyncha. Since the evolution of sex chromosomes in non-caenophidian snakes seems to be more complex than previously thought, we examined ten species of pythons and boas representing the families Boidae, Calabariidae, Candoiidae, Charinidae, Pythonidae, and Sanziniidae by conventional and molecular cytogenetic methods, aiming to reveal their sex chromosomes. Our results show that all examined species do not possess sex-specific differences in their genomes detectable by the applied cytogenetic methods, indicating the presence of poorly differentiated sex chromosomes or even the absence of sex chromosomes. Interestingly, fluorescence in situ hybridization with telomeric repeats revealed extensive distribution of interstitial telomeric repeats in eight species, which are likely a consequence of intra-chromosomal rearrangements.

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Cytogenetic markers reveal a reinforcement of variation in the tension zone between chromosome races in the brachypterous grasshopper Podisma sapporensis Shir. on Hokkaido Island

Scientific Reports ◽

10.1038/s41598-019-53416-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Beata Grzywacz ◽

Haruki Tatsuta ◽

Alexander G. Bugrov ◽

Elżbieta Warchałowska-Śliwa

Keyword(s):

Dna Sequences ◽

Genome Instability ◽

Significant Degree ◽

Hybrid Population ◽

Telomeric Dna ◽

Telomeric Repeats ◽

C Banding ◽

Rdna Sequences ◽

Rdna Sites ◽

Interstitial Telomeric Repeats

AbstractThe cytogenetic characteristics of the grasshopper Podisma sapporensis (two races 2n = 23♂ X0/XX and 2n = 22♂ neo-XY/neo-XX) were analysed through fluorescence in situ hybridization with rDNA and telomeric DNA probes, C-banding, fluorochrome and silver staining. For the first time, samples from the neighbourhood of a hybrid population (i.e., Mikuni Pass population) were studied. Our results indicated a significant degree of chromosomal differentiation between P. sapporensis races when comparing the number and position of the rDNA sites, as well as the heterochromatin composition and distribution obtained by C-banding and DAPI/CMA3 staining. Telomeric signals were usually detected at the distal and/or subdistal position of the autosomes; however, some chromosome ends lacked signals, probably due to a low number of telomeric repeats. On the other hand, telomeric DNA sequences were found as interstitial telomeric repeats in some autosomes, which can trigger a variety of genome instability. B chromosomes were found in specimens belonging to both main races from nine out of 22 localities. Four types of X chromosomes in the X0/XX race were identified. It was concluded that the physical mapping of rDNA sequences and heterochromatin are useful as additional markers for understanding the phylogeographic patterns of cytogenetic differentiation in P. sapporensis populations.

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Insight into the Chromosome Structure of the Cultivated Tetraploid Alfalfa (Medicago sativa subsp. sativa L.) by a Combined Use of GISH and FISH Techniques

Plants ◽

10.3390/plants9040542 ◽

2020 ◽

Vol 9 (4) ◽

pp. 542

Author(s):

Egizia Falistocco

Keyword(s):

In Situ Hybridization ◽

Medicago Sativa ◽

Tandem Repeats ◽

Chromosome Structure ◽

Substantial Part ◽

Telomeric Repeats ◽

Evolutionary Pathway ◽

Suitable Material ◽

Interstitial Telomeric Repeats

Cytogenetic research in Medicago sativa subsp. sativa L., the cultivated tetraploid alfalfa (2n = 4x = 32), has lagged behind other crops mostly due to the small size and the uniform morphology of its chromosomes. However, in the last decades, the development of molecular cytogenetic techniques based on in situ hybridization has largely contributed to overcoming these limitations. The purpose of this study was to extend our knowledge about the chromosome structure of alfalfa by using a combination of genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) techniques. The results of self-GISH (sGISH) suggested that a substantial part of the repetitive fraction of the genome of subsp. sativa is constituted by tandem repeats typical of satellite DNA. The coincidence of sGISH and C-banding patterns supported this assumption. The FISH mapping of the Arabidopsis-type TTTAGGG telomeric repeats demonstrated, for the first time, that the alfalfa telomeres consist of this type of sequence and revealed a massive presence of interstitial telomeric repeats (ITRs). In the light of this finding M. sativa appears to be a suitable material for studying the origin and function of such extra telomeric repeats. To further exploit this result, investigation will be extended to the diploid subspp. coerulea and falcata in order to explore possible connections between the distribution of ITRs, the ploidy level, and the evolutionary pathway of the taxa.

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Interstitial Telomeric Repeats Are Rare in Turtles

Genes ◽

10.3390/genes11060657 ◽

2020 ◽

Vol 11 (6) ◽

pp. 657 ◽

Cited By ~ 2

Author(s):

Lorenzo Clemente ◽

Sofia Mazzoleni ◽

Eleonora Pensabene Bellavia ◽

Barbora Augstenová ◽

Markus Auer ◽

...

Keyword(s):

In Situ Hybridization ◽

Karyotype Evolution ◽

Chromosomal Rearrangements ◽

Telomeric Repeats ◽

Squamate Reptiles ◽

Nucleoprotein Complexes ◽

Interstitial Telomeric Repeats ◽

Eukaryotic Organisms ◽

Genomic Regions

Telomeres are nucleoprotein complexes protecting chromosome ends in most eukaryotic organisms. In addition to chromosome ends, telomeric-like motifs can be accumulated in centromeric, pericentromeric and intermediate (i.e., between centromeres and telomeres) positions as so-called interstitial telomeric repeats (ITRs). We mapped the distribution of (TTAGGG)n repeats in the karyotypes of 30 species from nine families of turtles using fluorescence in situ hybridization. All examined species showed the expected terminal topology of telomeric motifs at the edges of chromosomes. We detected ITRs in only five species from three families. Combining our and literature data, we inferred seven independent origins of ITRs among turtles. ITRs occurred in turtles in centromeric positions, often in several chromosomal pairs, in a given species. Their distribution does not correspond directly to interchromosomal rearrangements. Our findings support that centromeres and non-recombining parts of sex chromosomes are very dynamic genomic regions, even in turtles, a group generally thought to be slowly evolving. However, in contrast to squamate reptiles (lizards and snakes), where ITRs were found in more than half of the examined species, and birds, the presence of ITRs is generally rare in turtles, which agrees with the expected low rates of chromosomal rearrangements and rather slow karyotype evolution in this group.

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