Format

Send to

Choose Destination
Curr Biol. 2012 Apr 24;22(8):695-700. doi: 10.1016/j.cub.2012.02.052. Epub 2012 Mar 29.

Uridylation of miRNAs by hen1 suppressor1 in Arabidopsis.

Author information

1
Center for Plant Science Innovation and School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0660, USA.

Abstract

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.

PMID:
22464191
PMCID:
PMC3582666
DOI:
10.1016/j.cub.2012.02.052
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center