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Nuclear RNA export factor variant initiates piRNA-guided co-transcriptional silencing
- Publication Year :
- 2019
- Publisher :
- Cold Spring Harbor Laboratory, 2019.
-
Abstract
- SummaryThe PIWI-interacting RNA (piRNA) pathway preserves genomic integrity by repressing transposable elements (TEs) in animal germ cells. Among PIWI-clade proteins inDrosophila, Piwi transcriptionally silences its targets through interactions with cofactors, including Panoramix (Panx) and forms heterochromatin characterized by H3K9me3 and H1. Here, we identified Nxf2, a nuclear RNA export factor (NXF) variant, as a protein that forms complexes with Piwi, Panx, and p15. Panx-Nxf2-p15 complex formation is necessary in the silencing by stabilizing protein levels of Nxf2 and Panx. Notably, ectopic targeting of Nxf2 initiates co-transcriptional repression of the target reporter in a manner independent of H3K9me3 marks or H1. However, continuous silencing requires HP1a and H1. In addition, Nxf2 directly interacts with target TE transcripts in a Piwi-dependent manner. These findings suggest a model in which the Nxf2-Panx-p15 complex enforces the association of Piwi with target transcripts to trigger co-transcriptional repression, prior to heterochromatin formation in the nuclear piRNA pathway.HighlightsNxf2 plays an essential role in the Piwi–piRNA pathwayFormation of Piwi-Panx-Nxf2-p15 (PPNP) complexes stabilizes both Panx and Nxf2The PPNP complex triggers transcriptional silencing before heterochromatin formationNxf2 directly binds to target transcripts in a Piwi-dependent manner
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....2b366cb782b07b801e6d56af518c580d
- Full Text :
- https://doi.org/10.1101/605725