Yb Integrates piRNA Intermediates and Processing Factors into Perinuclear Bodies to Enhance piRISC Assembly

• Published in: Cell reports (Cambridge) Vol. 8; no. 1; pp. 103 - 113
• Main Authors: Murota, Yukiko, Ishizu, Hirotsugu, Nakagawa, Shinichi, Iwasaki, Yuka W., Shibata, Shinsuke, Kamatani, Miharu K., Saito, Kuniaki, Okano, Hideyuki, Siomi, Haruhiko, Siomi, Mikiko C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 10.07.2014; Elsevier
• Subjects: Animals; Argonaute Proteins - genetics; Argonaute Proteins - metabolism; Cells, Cultured; Drosophila - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Female; Ovary - cytology; Ovary - metabolism; Protein Binding; RNA Helicases - genetics; RNA Helicases - metabolism; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; RNA-Induced Silencing Complex - metabolism
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2014.05.043

PIWI-interacting RNAs (piRNAs) direct Piwi to repress transposons and maintain genome integrity in Drosophila ovarian somatic cells. piRNA maturation and association with Piwi occur at perinuclear Yb bodies, the centers of piRNA biogenesis. Here, we show that piRNA intermediates arising from the piRNA cluster flamenco (flam) localize to perinuclear foci adjacent to Yb bodies, termed Flam bodies. RNAi-based screening of piRNA factors revealed that Flam body formation depends on Yb, the core component of Yb bodies, while Piwi and another Yb body component, Armitage, are dispensable for formation. Abolishing the RNA-binding activity of Yb disrupts both Flam bodies and Yb bodies. Yb directly binds flam, but not transcripts from neighboring protein-coding genes. Thus, Yb integrates piRNA intermediates and piRNA processing factors selectively into Flam bodies and Yb bodies, respectively. We suggest that Yb is a key upstream factor in the cytoplasmic phase of the piRNA pathway in ovarian somatic cells. [Display omitted] •piRNA intermediates localize to perinuclear Flam bodies adjacent to Yb bodies•The RNA-binding activity of Yb is required for Flam body and Yb body formation•Yb directly binds flam transcripts, but not neighboring protein-coding gene mRNAs•Yb is the most upstream factor in the cytoplasmic phase of the piRNA pathway piRNAs form complexes with Piwi protein and direct these piRISCs to repress transposons and maintain genome integrity in the gonads. piRNA maturation and piRISC formation occur at Yb bodies. In this study, Murota et al. find that piRNA intermediates arising from the flam locus localize to Flam bodies adjacent to Yb bodies. Yb, crucial for piRNA-mediated silencing, integrates piRNA intermediates and piRNA factors selectively into Flam bodies and Yb bodies, respectively.