Open AccessYb body assembly on theflamencopiRNA precursor transcripts reduces genic piRNA production
Author(s) -
Olesya Sokolova,
Artem Ilyin,
Anastasiya Poltavets,
Valentienasheva,
Elena A. Mikhaleva,
Yuri Y. Shevelyov,
Mikhail S. Klenov
Publication year - 2019
Publication title -
molecular biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.463
H-Index - 225
eISSN - 1939-4586
pISSN - 1059-1524
DOI - 10.1091/mbc.e17-10-0591
Subject(s) - biology , piwi interacting rna , microbiology and biotechnology , gene , transposable element , rna , biogenesis , genetics , rna interference , mutant
In Drosophila ovarian somatic cells, PIWI-interacting small RNAs (piRNAs) against transposable elements are mainly produced from the ∼180-kb flamenco ( flam) locus. flam transcripts are gathered into foci, located close to the nuclear envelope, and processed into piRNAs in the cytoplasmic Yb bodies. The mechanism of Yb body formation remains unknown. Using RNA fluorescence in situ hybridization, we found that in the follicle cells of ovaries the 5′-ends of flam transcripts are usually located in close proximity to the nuclear envelope and outside of Yb bodies, whereas their extended downstream regions mostly overlap with Yb bodies. In flam KG mutant ovaries, flam transcripts containing the first and, partially, second exons but lacking downstream regions are gathered into foci at the nuclear envelope, but Yb bodies are not assembled. Strikingly, piRNAs from the protein-coding gene transcripts accumulate at higher levels in flam KG ovaries indicating that piRNA biogenesis may occur without Yb bodies. We propose that normally in follicle cells, flam downstream transcript regions function not only as a substrate for generation of piRNAs but also as a scaffold for Yb body assembly, which competitively decreases piRNA production from the protein-coding gene transcripts. By contrast, in ovarian somatic cap and escort cells Yb body assembly does not require flam transcription.