A novel 5'-hydroxyl dinucleotide hydrolase activity for the DXO/Rai1 family of enzymes.
Nucleic Acids Res
; 48(1): 349-358, 2020 01 10.
Article
em En
| MEDLINE
| ID: mdl-31777937
ABSTRACT
Modifications at the 5'-end of RNAs play a pivotal role in determining their fate. In eukaryotes, the DXO/Rai1 family of enzymes removes numerous 5'-end RNA modifications, thereby regulating RNA turnover. Mouse DXO catalyzes the elimination of incomplete 5'-end caps (including pyrophosphate) and the non-canonical NAD+ cap on mRNAs, and possesses distributive 5'-3' exoribonuclease activity toward 5'-monophosphate (5'-PO4) RNA. Here, we demonstrate that DXO also catalyzes the hydrolysis of RNAs bearing a 5'-hydroxyl group (5'-OH RNA). The crystal structure of DXO in complex with a 5'-OH RNA substrate mimic at 2.0 Å resolution provides elegant insight into the molecular mechanism of this activity. More importantly, the structure predicts that DXO first removes a dinucleotide from 5'-OH RNA. Our nuclease assays confirm this prediction and demonstrate that this 5'-hydroxyl dinucleotide hydrolase (HDH) activity for DXO is higher than the subsequent 5'-3' exoribonuclease activity for selected substrates. Fission yeast Rai1 also has HDH activity although it does not have 5'-3' exonuclease activity, and the Rat1-Rai1 complex can completely degrade 5'-OH RNA. An Arabidopsis DXO1 variant is active toward 5'-OH RNA but prefers 5'-PO4 RNA. Collectively, these studies demonstrate the diverse activities of DXO/Rai1 and expands the collection of RNA substrates that can undergo 5'-3' mediated decay.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
RNA Mensageiro
/
Proteínas Nucleares
/
Transativadores
/
Proteínas de Ligação a RNA
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Proteínas de Saccharomyces cerevisiae
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Proteínas de Arabidopsis
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Exorribonucleases
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Proteínas de Cloroplastos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos