Current Biology
Volume 29, Issue 15, 5 August 2019, Pages 2465-2476.e5
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Article
m5C Methylation Guides Systemic Transport of Messenger RNA over Graft Junctions in Plants

https://doi.org/10.1016/j.cub.2019.06.042Get rights and content
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Highlights

  • m5C methylation is highly enriched in transcripts moving from shoot to root

  • TCTP1 and HSC70.1 mRNAs are not graft mobile in RNA methylation-deficient mutants

  • TCTP1 is translated after transport in distinct root cells and affects root growth

Summary

In plants, transcripts move to distant body parts to potentially act as systemic signals regulating development and growth. Thousands of messenger RNAs (mRNAs) are transported across graft junctions via the phloem to distinct plant parts. Little is known regarding features, structural motifs, and potential base modifications of transported transcripts and how these may affect their mobility. We identified Arabidopsis thaliana mRNAs harboring the modified base 5-methylcytosine (m5C) and found that these are significantly enriched in mRNAs previously described as mobile, moving over graft junctions to distinct plant parts. We confirm this finding with graft-mobile methylated mRNAs TRANSLATIONALLY CONTROLLED TUMOR PROTEIN 1 (TCTP1) and HEAT SHOCK COGNATE PROTEIN 70.1 (HSC70.1), whose mRNA transport is diminished in mutants deficient in m5C mRNA methylation. Together, our results point toward an essential role of cytosine methylation in systemic mRNA mobility in plants and that TCTP1 mRNA mobility is required for its signaling function.

Keywords

mRNA transport
long-distance transport
m5C
mRNA methylation
phloem
plasmodesmata
mRNA modification
grafting
root development

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These authors contributed equally

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Present address: Department of Molecular Medicine, Medical School, University of Padua, via Gabelli 63, 35121 Padua, Italy

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