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bioRxiv · 10.1101/163030

Key role of piRNAs in telomeric chromatin maintenance and telomere nuclear positioning in Drosophila germline

Radion, E.·Morgunova, V.·Ryazansky, S.·Akulenko, N.·Lavrov, S.·Abramov, Y.·Olovnikov, I.·Kalmykova, A.
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Abstract

Telomeric small RNAs related to PIWI-interacting RNAs (piRNAs) were discovered in different species, however, their role in germline-specific telomere function remains poorly understood. Using a Drosophila model, we show that the piRNA pathway provides a strong germline-specific mechanism of telomere homeostasis. We show that telomeric retrotransposon arrays belong to a unique class of dual-strand piRNA clusters whose transcripts, required for telomere elongation, serve simultaneously as piRNA precursors and their only targets. However, the ability to produce piRNAs and bind Rhino - a germline-specific homolog of heterochromatic protein 1 (HP1) - varies along telomeres. Most likely, this heterogeneity is determined by the peculiarities of telomeric retrotransposons themselves. piRNAs play a pivotal role in the establishment and maintenance of telomeric and subtelomeric chromatin in the germline facilitating loading of HP1 and histone 3 lysine 9 trimethylation mark - highly conservative telomere components - at different telomeric regions. piRNA pathway disruption results in telomere dysfunction characterized by a loss of heterochromatic components and translocation of telomeres from the periphery to the nuclear interior but does not affect the telomere end capping.

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Radion, E., Morgunova, V., Ryazansky, S., Akulenko, N., Lavrov, S., Abramov, Y., Olovnikov, I., Kalmykova, A.. 2017-07-13. Key role of piRNAs in telomeric chromatin maintenance and telomere nuclear positioning in Drosophila germline. https://doi.org/10.1101/163030

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