Plant MicroRNAs Display Differential 3' Truncation and Tailing Modifications That Are ARGONAUTE1 Dependent and Conserved Across Species

Authors

Jixian Zhai, University of Delaware
Yuanyuan Zhao, University of California
Stacey A. Simon, University of Delaware
Sheng Huang, Iowa State University
Katherine Petsch, Cold Spring Harbor Laboratory
Siwaret Arikit, University of Delaware
Manoj Pillay, University of Delaware
Lijuan Ji, University of California
Meng Xie, University of Nebraska - Lincoln
Xiaofeng Cao, Chinese Academy of Sciences
Bin Yu, University of Nebraska - LincolnFollow
Marja Timmermans, Cold Spring Harbor Laboratory
Bing Yang, Iowa State University
Xuemei Chen, University of California
Blake C. Meyers, University of DelawareFollow

Date of this Version

7-2013

Citation

The Plant Cell, Vol. 25: July 2013, pp. 2417–2428.

Comments

Copyright 2013 American Society of Plant Biologists. Used by permission.

Abstract

Plant small RNAs are 3' methylated by the methyltransferase HUA1 ENHANCER1 (HEN1). In plant hen1 mutants, 3' modifications of small RNAs, including oligo-uridylation (tailing), are associated with accelerated degradation of microRNAs (miRNAs). By sequencing small RNAs of the wild type and hen1 mutants from Arabidopsis thaliana, rice (Oryza sativa), and maize (Zea mays), we found 39 truncation prior to tailing is widespread in these mutants. Moreover, the patterns of miRNA truncation and tailing differ substantially among miRNA families but are conserved across species. The same patterns are also observable in wild-type libraries from a broad range of species, only at lower abundances. ARGONAUTE (AGO1), even with defective slicer activity, can bind these truncated and tailed variants of miRNAs. An ago1 mutation in hen1 suppressed such 3' modifications, indicating that they occur while miRNAs are in association with AGO1, either during or after RNAinduced silencing complex assembly. Our results showed AGO1-bound miRNAs are actively 3' truncated and tailed, possibly reflecting the activity of cofactors acting in conserved patterns in miRNA degradation.