Uridylation of miRNAs by HEN1 SUPPRESSOR1 in arabidopsis

Guodong Ren, Xuemei Chen, Bin Yu

Research output: Contribution to journalArticlepeer-review

135 Scopus citations


HEN1-mediated 2′-O-methylation has been shown to be a key mechanism to protect plant microRNAs (miRNAs) and small interfering RNAs (siRNAs) as well as animal piwi-interacting RNAs (piRNAs) from degradation and 3′ terminal uridylation [1-8]. However, enzymes uridylating unmethylated miRNAs, siRNAs, or piRNAs in hen1 are unknown. In this study, a genetic screen identified a second-site mutation hen1 suppressor1-2 (heso1-2) that partially suppresses the morphological phenotypes of the hypomorphic hen1-2 allele and the null hen1-1 allele in Arabidopsis. HESO1 encodes a terminal nucleotidyl transferase that prefers to add untemplated uridine to the 3′ end of RNA, which is completely abolished by 2′-O-methylation. heso1-2 affects the profile of u-tailed miRNAs and siRNAs and increases the abundance of truncated and/or normal sized ones in hen1, which often results in increased total amount of miRNAs and siRNAs in hen1. In contrast, overexpressing HESO1 in hen1-2 causes more severe morphological defects and less accumulation of miRNAs. These results demonstrate that HESO1 is an enzyme uridylating unmethylated miRNAs and siRNAs in hen1. These observations also suggest that uridylation may destabilize unmethylated miRNAs through an unknown mechanism and compete with 3′-to-5′ exoribonuclease activities in hen1. This study shall have implications on piRNA uridylation in hen1 in animals.

Original languageEnglish (US)
Pages (from-to)695-700
Number of pages6
JournalCurrent Biology
Issue number8
StatePublished - Apr 24 2012
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)


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