Export of piRNA precursors by EJC triggers assembly of cytoplasmic Yb-body in Drosophila

• Published in: Nature communications 2016-12, Vol.7 (1), p.13739-13739, Article 13739
• Main Authors: Dennis, Cynthia, Brasset, Emilie, Sarkar, Arpita, Vaury, Chantal
• Format: Article
• Language: English
• Subjects: 14/19; 38; 38/1; 38/23; 38/32; 38/71; 38/77; 38/89; 38/91; 631/337; 631/337/176/2016; 631/337/384/2054; Active Transport, Cell Nucleus; Animals; Cell Nucleus - metabolism; Cytoplasm; Cytoplasm - metabolism; Drosophila melanogaster - cytology; Drosophila melanogaster - metabolism; Drosophila Proteins - metabolism; Exons - genetics; Female; Follicles; Genetics; Humanities and Social Sciences; Insects; Life Sciences; Localization; multidisciplinary; Ovarian Follicle - cytology; Ovarian Follicle - metabolism; Ovaries; Proteins; RNA polymerase; RNA Precursors - metabolism; RNA Processing, Post-Transcriptional - genetics; RNA Transport; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Small Interfering - metabolism; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms13739

PIWI-interacting RNAs (piRNAs) are effectors of transposable element (TE) silencing in the reproductive apparatus. In Drosophila ovarian somatic cells, piRNAs arise from longer single-stranded RNA precursors that are processed in the cytoplasm presumably within the Yb-bodies. piRNA precursors encoded by the flamenco ( flam ) piRNA cluster accumulate in a single focus away from their sites of transcription. In this study, we identify the exportin complex containing Nxf1 and Nxt1 as required for flam precursor nuclear export. Together with components of the exon junction complex (EJC), it is necessary for the efficient transfer of flam precursors away from their site of transcription. Indeed, depletion of these components greatly affects flam intra-nuclear transit. Moreover, we show that Yb-body assembly is dependent on the nucleo-cytoplasmic export of flam transcripts. These results suggest that somatic piRNA precursors are thus required for the assembly of the cytoplasmic transposon silencing machinery. In Drosophila ovarian follicle cells, piRNAs generated from RNA precursors are processed in cytoplasmic Yb-bodies. The authors identify the exportin and the exon junction complexes as required to transfer precursors to cytoplasm. They also show that Yb-body formation requires piRNA precursor export.