Telomere-specific non-LTR retrotransposons and telomere maintenance in the silkworm, Bombyx mori

Fujiwara, Haruhiko; Osanai, Mizuko; Matsumoto, Takumi; Kojima, Kenji

doi:10.1007/s10577-005-0990-9

Cited by 95 publications

(94 citation statements)

References 57 publications

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“…In the silkworm, Bombyx mori, two retrotransposons target telomere regions, but insert into the terminal array rather than attach to the chromosome tip (100,101). In addition, mammalian LINE elements have the capability of endonuclease-independent transposition and can attach themselves directly to chromosome ends with disrupted telomeres (102).…”

Section: Evolution Of Drosophila Telomeresmentioning

confidence: 99%

Drosophila telomeres: an exception providing new insights

2007

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SummaryDrosophila telomeres are comprised of DNA sequences that differ dramatically from those of other eukaryotes. Telomere functions, however, are similar to those found in telomerase-based telomeres, even though the underlying mechanisms may differ. Drosophila telomeres use arrays of retrotransposons to maintain chromosome length, while nearly all other eukaryotes rely on telomerase-generated short repeats. Regardless of the DNA sequence, several end-binding proteins are evolutionarily conserved. Away from the end, the Drosophila telomeric and subtelomeric DNA sequences are complexed with unique combinations of proteins that also modulate chromatin structure elsewhere in the genome. Maintaining and regulating the transcriptional activity of the telomeric retrotransposons in Drosophila requires specific chromatin structures, and while telomeric silencing spreads from the terminal repeats in yeast, the source of telomeric silencing in Drosophila is the subterminal arrays. However, the subterminal arrays in both species may be involved in telomere-telomere associations and/or communication.

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Section: Evolution Of Drosophila Telomeresmentioning

confidence: 99%

Drosophila telomeres: an exception providing new insights

2007

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“…In some species, the telomeric repeats are interrupted by telomere-specific non-long terminal repeat (non-LTR) retrotransposons (Fig. 1B): SART and TRAS in Bombyx mori, 6 Zepp in Chlorella vulgaris, 7 GilM and GilT in Giardia lamblia, 8 and Penelope-like elements in diverse eukaryotes. 9 When telomerase activity is low, telomere length is also maintained by a recombination-mediated mechanism, 10,11 or, in some species, by both insertion of telomeric retrotransposons into telomerase-synthesized repeats and recombination.…”

Section: Introductionmentioning

confidence: 99%

Telomere maintenance in Drosophila: Rapid transposon evolution at chromosome ends

Villasanté

Pablos²,

Méndez-Lago³

et al. 2008

Cell Cycle

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The maintenance of terminal sequences is an important role of the telomere, since it prevents the loss of internal regions that encode essential genes. In most eukaryotes, this is accomplished by the telomerase. However, telomere length can also be maintained by other mechanisms, such as homologous recombination and transposition of telomeric retrotransposons to the chromosome ends. A remarkable situation is the case of Drosophila, where telomerase was lost, and thus telomeres managed to be maintained by occasional retrotransposition of telomeric elements to the receding ends. In the recent analysis of 12 Drosophila genomes, the multiplicity of autonomous and non-autonomous telomere-specific retrotransposons has revealed extensive and rapid evolution of telomeric DNA. The phylogenetic relationship among these telomeric retrotransposons is congruent with the species phylogeny, suggesting that they have been vertically transmitted from a common ancestor. In this review, we also suggest that the formation of a non-canonical DNA structure at Drosophila telomeres could be the way to protect the ends.

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“…Manual assembly of the proximal regions of multiple telomeres beyond the ends of the assembled scaffolds (Supplementary Information) reveals TCAGG repeats interrupted by full-length and 59-truncated non-LTR retrotransposons belonging to the R1 clade, best known for insertions in the rDNA locus 14 . Tribolium telomeres range in length from 15 kilobases (kb) upwards and probably represent a stage intermediate to the loss of telomeres and telomerase in Diptera compared with the simple canonical structure of the honeybee 15 or the more regular insertion of non-LTR retrotransposons into the simple repeats of the silkmoth 16 .…”

mentioning

confidence: 99%

The genome of the model beetle and pest Tribolium castaneum

2008

Nature

1,251

694

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Tribolium castaneum is a member of the most species-rich eukaryotic order, a powerful model organism for the study of generalized insect development, and an important pest of stored agricultural products. We describe its genome sequence here. This omnivorous beetle has evolved the ability to interact with a diverse chemical environment, as shown by large expansions in odorant and gustatory receptors, as well as P450 and other detoxification enzymes. Development in Tribolium is more representative of other insects than is Drosophila, a fact reflected in gene content and function. For example, Tribolium has retained more ancestral genes involved in cell-cell communication than Drosophila, some being expressed in the growth zone crucial for axial elongation in short-germ development. Systemic RNA interference in T. castaneum functions differently from that in Caenorhabditis elegans, but nevertheless offers similar power for the elucidation of gene function and identification of targets for selective insect control.

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Telomere-specific non-LTR retrotransposons and telomere maintenance in the silkworm, Bombyx mori

Cited by 95 publications

References 57 publications

Drosophila telomeres: an exception providing new insights

Drosophila telomeres: an exception providing new insights

Telomere maintenance in Drosophila: Rapid transposon evolution at chromosome ends

The genome of the model beetle and pest Tribolium castaneum

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