5'-3' exoribonuclease (IPR027073)

Short name: 5_3_exoribonuclease

Overlapping homologous superfamilies


Family relationships


This entry includes 5'-3'exoribonuclease type 1 and type 2. Putative viral exonucleases 059L and 012L, plant Xrn3 and Xrn4 also belong to this family. 5'-3'-exoribonucleases are enzymes that degrade RNA by removing terminal nucleotides from the 5' end. An exosome and a 5'-3'-exoribonuclease are important in the degradation of very unstable transcripts [PMID: 18481995].

5'-3'exoribonuclease type 1 (Xrn1, also known as kem1) occurs in animal and fungal lineages. In Saccharomyces cerevisiae, Xrn1 can be activated by Dcs1, a non-essential hydrolase that involved in mRNA decapping. The activation of Xrn1 by Dcs1 is important for respiration [PMID: 22570495].

5'-3' exoribonuclease type 2 (Xrn2, also known as Rat1) occurs in animal, plant and fungal lineages. In Saccharomyces cerevisiae, Rat1 serves to terminate RNA polymerase II (RNAPII) molecules engaged in the production of uncapped RNA [PMID: 20188675].

The concomitant loss of Xrn4 and ABH1/CBP80, a subunit of the mRNA cap binding complex, results in Arabidopsis plants manifesting myriad developmental defects [PMID: 18486559], suggesting that this enzyme is not only important for RNA processing.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.