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Primary transcripts of microRNAs encode regulatory peptides


DominiqueLauressergues, Jean-MaloCouzigou, Hélène SanClemente, Yves Martinez,ChristopheDunand, GuillaumeBécard & Jean-PhilippeCombier

Nature520,90–93(02 April 2015) doi:10.1038/nature14346


MicroRNAs (miRNAs) are small regulatory RNAmolecules that inhibit the expression of specific target genes by binding toand cleaving their messenger RNAs or otherwise inhibiting their translationinto proteins1. miRNAs are transcribed as much larger primarytranscripts (pri-miRNAs), the function of which is not fully understood. Herewe show that plant pri-miRNAs contain short open reading frame sequences thatencode regulatory peptides. The pri-miR171b of Medicago truncatula andthe pri-miR165a of Arabidopsis thaliana produce peptides, which we termmiPEP171b and miPEP165a, respectively, that enhance the accumulation of theircorresponding mature miRNAs, resulting in downregulation of target genesinvolved in root development. The mechanism of miRNA-encoded peptide (miPEP)action involves increasing transcription of the pri-miRNA. Five otherpri-miRNAs of A. thaliana and M. truncatula encode active miPEPs,suggesting that miPEPs are widespread throughout the plant kingdom. SyntheticmiPEP171b and miPEP165a peptides applied to plants specifically trigger theaccumulation of miR171b and miR165a, leading to reduction of lateral rootdevelopment and stimulation of main root growth, respectively, suggesting thatmiPEPs might have agronomical applications.