The PIWI-interacting RNA (piRNA) pathway is a small RNA-based immune system that controls the expression of transposons and maintains genome integrity in animal gonads. In Drosophila, piRNA-guided silencing is achieved, in part, via co-transcriptional repression of transposons by Piwi. This depends on Panoramix (Panx); however, precisely how an RNA binding event silences transcription remains to be determined. Here we show that Nuclear Export Factor 2 (Nxf2) and its co-factor, Nxt1, form a complex with Panx and are required for co-transcriptional silencing of transposons in somatic and germline cells of the ovary. Tethering of Nxf2 or Nxt1 to RNA results in silencing of target loci and the concomitant accumulation of repressive chromatin marks. Nxf2 and Panx proteins are mutually required for proper localization and stability. We mapped the protein domains crucial for the Nxf2/Panx complex formation and show that the amino-terminal portion of Panx is sufficient to induce transcriptional silencing.
Sequencing data reported in this paper has been deposited in GEO under accession number GSE121661. Mass Spectrometry data has been deposited to the PRIDE Archive (accession number PXD011415)
piRNA-guided co-transcriptional silencing coopts nuclear export factorsNCBI Gene Expression Omnibus, GSE121661.
piRNA-guided co-transcriptional silencing coopts nuclear export factorsPRIDE Archive, PXD011415.
- Gregory J Hannon
- Gregory J Hannon
- Filippo Ciabrelli
- Marzia Munafò
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Torben Heick Jensen, Aarhus University, Denmark
© 2019, Fabry et al.
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