Format

Send to

Choose Destination
Cell. 2019 Aug 8;178(4):964-979.e20. doi: 10.1016/j.cell.2019.07.007.

A Heterochromatin-Specific RNA Export Pathway Facilitates piRNA Production.

Author information

1
Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohrgasse 3, 1030 Vienna, Austria.
2
Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohrgasse 3, 1030 Vienna, Austria. Electronic address: pra@mbg.au.dk.
3
Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohrgasse 3, 1030 Vienna, Austria; Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
4
Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna BioCenter (VBC), Dr. Bohrgasse 3, 1030 Vienna, Austria. Electronic address: julius.brennecke@imba.oeaw.ac.at.

Abstract

PIWI-interacting RNAs (piRNAs) guide transposon silencing in animals. The 22-30 nt piRNAs are processed in the cytoplasm from long non-coding RNAs that often lack RNA processing hallmarks of export-competent transcripts. By studying how these transcripts achieve nuclear export, we uncover an RNA export pathway specific for piRNA precursors in the Drosophila germline. This pathway requires Nxf3-Nxt1, a variant of the hetero-dimeric mRNA export receptor Nxf1-Nxt1. Nxf3 interacts with UAP56, a nuclear RNA helicase essential for mRNA export, and CG13741/Bootlegger, which recruits Nxf3-Nxt1 and UAP56 to heterochromatic piRNA source loci. Upon RNA cargo binding, Nxf3 achieves nuclear export via the exportin Crm1 and accumulates together with Bootlegger in peri-nuclear nuage, suggesting that after export, Nxf3-Bootlegger delivers precursor transcripts to the piRNA processing sites. These findings indicate that the piRNA pathway bypasses nuclear RNA surveillance systems to export unprocessed transcripts to the cytoplasm, a strategy also exploited by retroviruses.

KEYWORDS:

Crm1; Drosophila germline; NXF proteins; RNA export; RNA surveillance; UAP56; heterochromatin; piRNA cluster; piRNA pathway; transposon control

PMID:
31398345
DOI:
10.1016/j.cell.2019.07.007

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center