RT Journal Article
SR Electronic
T1 The nascent RNA binding complex SFiNX licenses piRNA-guided heterochromatin formation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 609693
DO 10.1101/609693
A1 Julia Batki
A1 Jakob Schnabl
A1 Juncheng Wang
A1 Dominik Handler
A1 Veselin I. Andreev
A1 Christian E. Stieger
A1 Maria Novatchkova
A1 Lisa Lampersberger
A1 Kotryna Kauneckaite
A1 Karl Mechtler
A1 Dinshaw J. Patel
A1 Julius Brennecke
YR 2019
UL http://biorxiv.org/content/early/2019/04/17/609693.abstract
AB The PIWI-interacting RNA (piRNA) pathway protects animal genome integrity in part through establishing repressive heterochromatin at transposon loci. Silencing requires piRNA-guided targeting of nuclear PIWI proteins to nascent transposon transcripts, yet the subsequent molecular events are not understood. Here, we identify SFiNX (Silencing Factor interacting Nuclear eXport variant), an interdependent protein complex required for Piwi-mediated co-transcriptional silencing in Drosophila. SFiNX consists of Nxf2-Nxt1, a gonad-specific variant of the heterodimeric mRNA export receptor Nxf1-Nxt1, and the Piwi-associated protein Panoramix. SFiNX mutant flies are sterile and exhibit transposon de-repression because piRNA-loaded Piwi is unable to establish heterochromatin. Within SFiNX, Panoramix recruits the cellular heterochromatin machinery, while Nxf2 binds the nascent target RNA and licenses co-transcriptional silencing. Our results reveal an unexpected, RNA-export independent role for Nxf2 in nuclear small RNA biology and suggest that NXF-variants, which have largely unknown function in animals, are functionally linked to the genome-transposon conflict.