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Locus-specific variation in piRNA production in different mouse strains.

ABSTRACT: The PIWI-interacting small RNA (piRNA) pathway silences transposons in the germline of almost all animals. Contrary to the conservation of the pathway, piRNA-producing loci turn over fast between species, even though some of these loci are found in syntenic regions and even when the sequences of the piRNA precursor transcripts are conserved. The evolution of piRNAs is a remarkable, yet poorly understood, characteristic of this class of small RNAs. In order to learn about the sequence changes that contribute to the fast evolution of piRNAs, we set out to analyse piRNA expression between genetically different mice. Here we report the sequencing and analysis of small RNAs from the mouse male germline of four classical inbred strains, one inbred wild-derived strain and one outbred strain. We show that the majority of piRNAs are produced from the same loci, with similar levels, in different mice, with notable exceptions. We find that genetic differences between individuals cause variation in piRNA expression from specific loci. We report differences in piRNA production at loci of the mouse genome with endogenous retrovirus insertions in the same strand as the piRNA-precursor transcripts. These results suggest that at least one of the piRNA biogenesis pathways identifies transcripts as piRNA precursors when these transcripts are post-transcriptionally controlled by strand-specific regulatory elements of endogenous retroviruses. Our findings provide evidence that transposable elements are major – although not the only – drivers of piRNA diversification in mammals.

ORGANISM(S): Mus musculus

PROVIDER: GSE215030 | GEO | 2023/09/22

REPOSITORIES: GEO

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