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Title: A nuclear import pathway exploited by pathogenic noncoding RNAs
Abstract

The prevailing view of intracellular RNA trafficking in eukaryotic cells is that RNAs transcribed in the nucleus either stay in the nucleus or cross the nuclear envelope, entering the cytoplasm for function. However, emerging evidence illustrates that numerous functional RNAs move in the reverse direction, from the cytoplasm to the nucleus. The mechanism underlying RNA nuclear import has not been well elucidated. Viroids are single-stranded circular noncoding RNAs that infect plants. Using Nicotiana benthamiana, tomato (Solanum lycopersicum), and nuclear-replicating viroids as a model, we showed that cellular IMPORTIN ALPHA-4 (IMPa-4) is likely involved in viroid RNA nuclear import, empirically supporting the involvement of Importin-based cellular pathway in RNA nuclear import. We also confirmed the involvement of a cellular protein (viroid RNA-binding protein 1 [VIRP1]) that binds both IMPa-4 and viroids. Moreover, a conserved C-loop in nuclear-replicating viroids serves as a key signal for nuclear import. Disrupting C-loop impairs VIRP1 binding, viroid nuclear accumulation, and infectivity. Further, C-loop exists in a subviral satellite noncoding RNA that relies on VIRP1 for nuclear import. These results advance our understanding of subviral RNA infection and the regulation of RNA nuclear import.

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Award ID(s):
2145967
NSF-PAR ID:
10372679
Author(s) / Creator(s):
; ; ; ; ; ;
Publisher / Repository:
Oxford University Press
Date Published:
Journal Name:
The Plant Cell
Volume:
34
Issue:
10
ISSN:
1040-4651
Page Range / eLocation ID:
p. 3543-3556
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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