Distinct and Cooperative Activities of HESO1 and URT1 Nucleotidyl Transferases in MicroRNA Turnover in Arabidopsis

Authors

• Bin Tu, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside; Rice Research Institute, Sichuan Agricultural University
• Li Liu, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside; Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences, Shenzhen University
• Chi Xu, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences, Shenzhen University
• Jixinan Zhai, Department of Plant & Soil Sciences, and Delaware Biotechnology Institute, University of Delaware
• Shengben Li, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside
• Miguel A. Lopez, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside
• Yuanyuan Zhao, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside
• Yu Yu, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside
• Vanitharani Ramachandran, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside
• Guodong Ren, Center for Plant Science Innovation & School of Biological Sciences, University of Nebraska- Lincoln
• Bin Yu, University of Nebraska-LincolnFollow
• Shigui Li, Rice Research Institute, Sichuan Agricultural University
• Blake C. Meyers, University of DelawareFollow
• Beixin Mo, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences, Shenzhen UniversityFollow
• Xuemei Chen, Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California; Howard Hughes Medical Institute, University of CaliforniaFollow

Document Type

Article

Date of this Version

2015

Citation

PLOS Genetics, 2015

Comments

U.S. Government work

Abstract

3’ uridylation is increasingly recognized as a conserved RNA modification process associated with RNA turnover in eukaryotes. 2’-O-methylation on the 3’ terminal ribose protects micro(mi)RNAs from 3’ truncation and 3’ uridylation in Arabidopsis. Previously, we identified HESO1 as the nucleotidyl transferase that uridylates most unmethylated miRNAs in vivo, but substantial 3’ tailing of miRNAs still remains in heso1 loss-of-function mutants. In this study, we found that among nine other potential nucleotidyl transferases, UTP:RNA URIDYLYLTRANSFERASE 1 (URT1) is the single most predominant nucleotidyl transferase that tails miRNAs. URT1 and HESO1 prefer substrates with different 3’ end nucleotides in vitro and act cooperatively to tail different forms of the same miRNAs in vivo. Moreover, both HESO1 and URT1 exhibit nucleotidyl transferase activity on AGO1-bound miRNAs. Although these enzymes are able to add long tails to AGO1-bound miRNAs, the tailed miRNAs remain associated with AGO1. Moreover, tailing of AGO1-bound miRNA165/6 drastically reduces the slicing activity of AGO1-miR165/6, suggesting that tailing reduces miRNA activity. However, monouridylation of miR171a by URT1 endows the miRNA the ability to trigger the biogenesis of secondary siRNAs. Therefore, 3’ tailing could affect the activities of miRNAs in addition to leading to miRNA degradation.