Inter-telomeric recombination is present in telomerase-positive human cells

Dlaska, Margit; Schöffski, Patrick; Bechter, Oliver

doi:10.4161/cc.25136

Cited by 4 publications

(3 citation statements)

References 58 publications

(72 reference statements)

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“…Organisms that have telomerase-generated telomeric DNA sequences also appear to have an alternative mechanism for lengthening telomeres (Royle et al 2009). For example, in yeast and human tumors, alternative process for the maintenance of telomeric sequences may occur readily even in the presence of telomerase (Teng and Zakian 1999;Cesare and Reddel 2010;Dlaska et al 2013). Thus, it is not surprising that over evolutionary time, telomerase-generated telomeric DNA sequences have been independently lost in Hymenoptera and other insect groups.…”

Section: Discussionmentioning

confidence: 99%

Are the TTAGG and TTAGGG telomeric repeats phylogenetically conserved in aculeate Hymenoptera?

Menezes

Bardella

Cabral-de-Mello

et al. 2017

Sci Nat

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Despite the (TTAGG) telomeric repeat supposed being the ancestral DNA motif of telomeres in insects, it was repeatedly lost within some insect orders. Notably, parasitoid hymenopterans and the social wasp Metapolybia decorata (Gribodo) lack the (TTAGG) sequence, but in other representatives of Hymenoptera, this motif was noticed, such as different ant species and the honeybee. These findings raise the question of whether the insect telomeric repeat is or not phylogenetically predominant in Hymenoptera. Thus, we evaluated the occurrence of both the (TTAGG) sequence and the vertebrate telomere sequence (TTAGGG) using dot-blotting hybridization in 25 aculeate species of Hymenoptera. Our results revealed the absence of (TTAGG) sequence in all tested species, elevating the number of hymenopteran families lacking this telomeric sequence to 13 out of the 15 tested families so far. The (TTAGGG) was not observed in any tested species. Based on our data and compiled information, we suggest that the (TTAGG) sequence was putatively lost in the ancestor of Apocrita with at least two subsequent independent regains (in Formicidae and Apidae).

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Section: Discussionmentioning

confidence: 99%

Are the TTAGG and TTAGGG telomeric repeats phylogenetically conserved in aculeate Hymenoptera?

Menezes

Bardella

Cabral-de-Mello

et al. 2017

Sci Nat

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“…Given its wide distribution, telomerase obviously arose very early in the evolution of eukaryotes; it may also provide greater stringency or efficiency in the maintenance of the canonical sequence required by a sequence-specific capping complex than alternatives, such as recombination. These alternative mechanisms may occur readily, as seen in yeast (Teng and Zakian 1999) and human tumors (Cesare and Reddel 2010) even in the presence of telomerase (Dlaska et al 2013). In addition, short telomeres or loss of telomerase from human cancer cells may stimulate alternative lengthening of telomeres (ALT) mechanisms (Morrish and Greider 2009; Queisser et al 2013).…”

Section: Discussionmentioning

confidence: 99%

Telomerase lost?

2015

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Telomerase and telomerase-generated telomeric DNA sequences are widespread throughout eukaryotes, yet they are not universal. Neither telomerase nor the simple DNA repeats associated with telomerase have been found in some plant and animal species. Telomerase was likely lost from Diptera before the divergence of Diptera and Siphonaptera, some 260 million years ago. Even so, Diptera is one of the most successful animal orders, making up 11% of known animal species. In addition, many species of Coleoptera and Hemiptera seem to lack canonical telomeric repeats at their chromosome ends. These and other insects that appear to lack canonical terminal repeat sequences account for another 10-15% of animal species. Conversely, the silk moth Bombyx mori maintains canonical telomeric sequences at its chromosome ends but seems to lack a functional telomerase. We speculate that a telomere-specific capping complex that recognizes the telomeric repeats and protects chromosome ends is the determining factor in maintaining canonical telomeric sequences and that telomerase is an early and efficacious mechanism for satisfying the needs of capping complex. There are alternate mechanisms for maintaining chromosome ends that do not depend on telomerase, such as recombination found in some human cancer cells and yeast mutants. These mechanisms may maintain the canonical telomeric repeats or allow the terminal sequence to evolve when specificity of the capping complex for terminal repeat sequences is weak.

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“…For example, it can be used as adjuvant to conventional cancer treatments, such as chemo-and radiotherapy, because it does not interfere with those treatment procedures and can add a new dimension to the therapy. We suggest that for the PdTMPyP4/PLGA implant to be a part of a comprehensive and potentially curative treatment strategy, it is equally important to address the ALT telomere-lengthening mechanism that is active regardless of whether telomerase is active or inhibited (Dlaska et al 2013;Jeyapalan et al 2005;Bechter et al 2004Bechter et al , 2004Henson et al 2002) and that predominates in certain cancer types (McDonald et al 2010). ALT activation and its elongation of telomeres presents an obstacle to the achievement of complete tumor remission.…”

Section: Discussionmentioning

confidence: 96%