TY - JOUR TI - piRNA-guided co-transcriptional silencing coopts nuclear export factors AU - Fabry, Martin H AU - Ciabrelli, Filippo AU - MunafoĢ€, Marzia AU - Eastwood, Evelyn L AU - Kneuss, Emma AU - Falciatori, Ilaria AU - Falconio, Federica A AU - Hannon, Gregory J AU - Czech, Benjamin A2 - Jensen, Torben Heick A2 - Manley, James L VL - 8 PY - 2019 DA - 2019/06/20 SP - e47999 C1 - eLife 2019;8:e47999 DO - 10.7554/eLife.47999 UR - https://doi.org/10.7554/eLife.47999 AB - 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. KW - piRNA pathway KW - transcriptional gene silencing KW - transposon control KW - nuclear export factor KW - PIWI proteins JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -