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Regulation of pri-miRNA processing by the hnRNP-like protein AtGRP7 in Arabidopsis

Authors :
Tino Köster
Dorothee Staiger
Ivo Grosse
Katja Meyer
Detlef Weigel
Martina Lummer
Corinna Speth
Lisa M. Smith
Claus Weinholdt
Source :
Nucleic Acids Research
Publication Year :
2014
Publisher :
Oxford University Press (OUP), 2014.

Abstract

The hnRNP-like glycine-rich RNA-binding protein AtGRP7 regulates pre-mRNA splicing in Arabidopsis. Here we used small RNA-seq to show that AtGRP7 also affects the miRNA inventory. AtGRP7 overexpression caused a significant reduction in the level of 30 miRNAs and an increase for 14 miRNAs with a minimum log2 fold change of ±0.5. Overaccumulation of several pri-miRNAs including pri-miR398b, pri-miR398c, pri-miR172b, pri-miR159a and pri-miR390 at the expense of the mature miRNAs suggested that AtGRP7 affects pri-miRNA processing. Indeed, RNA immunoprecipitation revealed that AtGRP7 interacts with these pri-miRNAs in vivo. Mutation of an arginine in the RNA recognition motif abrogated in vivo binding and the effect on miRNA and pri-miRNA levels, indicating that AtGRP7 inhibits processing of these pri-miRNAs by direct binding. In contrast, pri-miRNAs of selected miRNAs that were elevated or not changed in response to high AtGRP7 levels were not bound in vivo. Reduced accumulation of miR390, an initiator of trans-acting small interfering RNA (ta-siRNA) formation, also led to lower TAS3 ta-siRNA levels and increased mRNA expression of the target AUXIN RESPONSE FACTOR4. Furthermore, AtGRP7 affected splicing of pri-miR172b and pri-miR162a. Thus, AtGRP7 is an hnRNP-like protein with a role in processing of pri-miRNAs in addition to its role in pre-mRNA splicing.

Details

ISSN :
13624962 and 03051048
Volume :
42
Database :
OpenAIRE
Journal :
Nucleic Acids Research
Accession number :
edsair.doi.dedup.....01a1c7f2479f0f7ff5f30a082026a0d2
Full Text :
https://doi.org/10.1093/nar/gku716