InterPro domain: IPR039039

Yeast RAI1 is homologous to Caenorhabditis elegans DOM-3 and human DOM3Z (DXO). They have both decapping and 5'-3' exoribonuclease activity and are a component of the mRNA 5'-end capping quality control mechanism [ 1 , 2 ]. RAI1 is a single-copy gene in most organisms; however S. cerevisiae contains a second homologue, DXO1, which also possesses decapping and 5'-3' exoribonuclease activity, whereas RAI1 has decapping and pyrophosphohydrolase activities [ 3 ]. This domain is also found in DXO1 homologue from Arabidopsis [ 3 ].

This entry also includes protein Cutoff (Cuff) from Drosophila. Differently from Rai1, Cuff does not display a Dom3Z domain, which is critical for Rai1 activity. Rai1 has been shown to regulate piRNA cluster expression and piRNA production in the Drosophila germline [ 4 ].

1. Dxo1 is a new type of eukaryotic enzyme with both decapping and 5'-3' exoribonuclease activity. Nat. Struct. Mol. Biol. 19, 1011-7
2. Structural and biochemical studies of the distinct activity profiles of Rai1 enzymes. Nucleic Acids Res. 43, 6596-606
3. Arabidopsis DXO1 links RNA turnover and chloroplast function independently of its enzymatic activity. Nucleic Acids Res 47, 4751-4764
4. The Cutoff protein regulates piRNA cluster expression and piRNA production in the Drosophila germline. EMBO J. 30, 4601-15