Chimeric double-stranded RNA-specific adenosine deaminase ADAR1 proteins reveal functional selectivity of double-stranded RNA-binding domains from ADAR1 and protein kinase PKR
AUTOR(ES)
Liu, Yong
FONTE
The National Academy of Sciences
RESUMO
The RNA-specific adenosine deaminase (ADAR1) and the RNA-dependent protein kinase (PKR) are both interferon-inducible double-stranded (ds) RNA-binding proteins. ADAR1, an RNA editing enzyme that converts adenosine to inosine, possesses three copies of a dsRNA-binding motif (dsRBM). PKR, a regulator of translation, has two copies of the highly conserved dsRBM motif. To assess the functional selectivity of the dsRBM motifs in ADAR1, we constructed and characterized chimeric proteins in which the dsRBMs of ADAR1 were substituted with those of PKR. Recombinant PKR-ADAR1 chimeras retained significant RNA adenosine deaminase activity measured with a synthetic dsRNA substrate when the spacer region between the RNA-binding and catalytic domains of the deaminase was exactly preserved. However, with natural substrates, substitution of the first two dsRBMs of ADAR1 with those from PKR dramatically reduced site-selective editing activity at the R/G and (+)60 sites of the glutamate receptor B subunit pre-RNA and completely abolished editing of the serotonin 2C receptor (5-HT2CR) pre-RNA at the A site. Chimeric deaminases possessing only the two dsRBMs from PKR were incapable of editing either glutamate receptor B subunit or 5-HT2CR natural sites but edited synthetic dsRNA. Finally, RNA antagonists of PKR significantly inhibited the activity of chimeric PKR-ADAR1 proteins relative to wild-type ADAR1, further demonstrating the functional selectivity of the dsRBM motifs.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=18800Documentos Relacionados
- Mechanism of interferon action: functionally distinct RNA-binding and catalytic domains in the interferon-inducible, double-stranded RNA-specific adenosine deaminase.
- RNA-specific Adenosine Deaminase ADAR1 Suppresses Measles Virus-induced Apoptosis and Activation of Protein Kinase PKR*
- Cloning of cDNAs encoding mammalian double-stranded RNA-specific adenosine deaminase.
- Purification and properties of double-stranded RNA-specific adenosine deaminase from calf thymus.
- A new double-stranded RNA-binding protein that interacts with PKR
