Synergistic and independent actions of multiple terminal nucleotidyl transferases in 3’ tailing of small RNAs in Arabidopsis

Small silencing RNAs are key regulators of gene expression in both plants and animals. HEN1-mediated 3’ terminal 2’-O-methylation plays a crucial role in small RNA stability control. In the absence of HEN1, small RNAs are frequently uridylated (untemplated uridine addition) and trimmed, a phenomenon that is conserved across species. However, the underlying molecular mechanism is largely unknown. In this study, we have discovered UTP: RNA uridylyltransferase (URT1) acts redundantly with HESO1 in the uridylation of miRNAs, in addition to its role in oligo-adenylated mRNA uridylation. We show both common and distinctive features of URT1 and HESO1 in catalyzing miRNA uridylation. non coding RNA deep sequencing