Journal Article


Trypanosomes can initiate nuclear export co-transcriptionally

Abstract

The nuclear envelope serves as important messenger RNA (mRNA) surveillance system. In yeast and human, several control systems act in parallel to prevent nuclear export of unprocessed mRNAs. Trypanosomes lack homologues to most of the involved proteins and their nuclear mRNA metabolism is nonconventional exemplified by polycistronic transcription and mRNA processing by trans-splicing. We here visualized nuclear export in trypanosomes by intra- and intermolecular multi-colour single molecule FISH. We found that, in striking contrast to other eukaryotes, the initiation of nuclear export requires neither the completion of transcription nor splicing. Nevertheless, we show that unspliced mRNAs are mostly prevented from reaching the nucleus-distant cytoplasm and instead accumulate at the nuclear periphery in cytoplasmic nuclear periphery granules (NPGs). Further characterization of NPGs by electron microscopy and proteomics revealed that the granules are located at the cytoplasmic site of the nuclear pores and contain most cytoplasmic RNAbinding proteins but none of the major translation initiation factors, consistent with a function in preventing faulty mRNAs from reaching translation. Our data indicate that trypanosomes regulate the completion of nuclear export, rather than the initiation. Nuclear export control remains poorly understood, in any organism, and the described way of control may not be restricted to trypanosomes.

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Authors

Goos, Carina
Dejung, Mario
Wehman, Ann M.
M-Natus, Elisabeth
Schmidt, Johannes
Sunter, Jack
Engstler, Markus
Butter, Falk
Kramer, Susanne

Oxford Brookes departments

Faculty of Health and Life Sciences\Department of Biological and Medical Sciences

Dates

Year of publication: 2018
Date of RADAR deposit: 2018-11-19


Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 International License


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  • Owner: Joseph Ripp
  • Collection: Outputs
  • Version: 1 (show all)
  • Status: Live