InterPro domain: IPR017151

This entry includes 5'-3'exoribonuclease type 2 (Xrn2, also known as Rat1), which occurs in animal, plant and fungal lineages. They act as post-transcriptional gene silencing (PTGS) suppressors [ 1 ]. In Saccharomyces cerevisiae, Rat1 serves to terminate RNA polymerase II (RNAPII) molecules engaged in the production of uncapped RNA [ 2 ]. This entry also includes plant Xrn3 and Xrn4.

5'-3'-exoribonucleases are enzymes that degrade RNA by removing terminal nucleotides from the 5' end. Hydrolytic exoribonucleases, to which this entry belongs, produce nucleotide monosphosphates. An exosome and a 5'-3'-exoribonuclease are important in the degradation of very unstable transcripts [ 3 ].

1. Arabidopsis FIERY1, XRN2, and XRN3 are endogenous RNA silencing suppressors. Plant Cell 19, 3451-61
2. The yeast 5'-3' exonuclease Rat1p functions during transcription elongation by RNA polymerase II. Mol. Cell 37, 580-7
3. Control of mRNA degradation in trypanosomes. Biochem. Soc. Trans. 36, 520-1