Purification and Characterization of a Human RNA Adenosine Deaminase for Glutamate Receptor B Pre-mRNA Editing

• Published in: Proceedings of the National Academy of Sciences - PNAS 1997-04, Vol.94 (9), p.4354-4359
• Main Authors: Yang, Jing-Hua, Sklar, Pamela, Axel, Richard, Maniatis, Tom
• Format: Article
• Language: English
• Subjects: Adenosine - metabolism; Adenosine Deaminase - genetics; Adenosine Deaminase - isolation & purification; Adenosine Deaminase - metabolism; Amino acids; Base Sequence; Biochemistry; Biological Sciences; Chromatography; Cloning, Molecular; Double stranded RNA; Genetic mutation; Glutamate receptors; HeLa Cells; Humans; Inosine - metabolism; Molecular Sequence Data; Mutation; Nucleotides; Phenyls; Proteins; Receptors, Glutamate - genetics; Recombinant Proteins - metabolism; Ribonucleic acid; RNA; RNA Editing; RNA Precursors - metabolism; RNA, Messenger - metabolism; RNA-Binding Proteins; Substrate Specificity
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.9.4354

The glutamate receptor subunit B (GluR-B) pre-mRNA is edited at two adenosine residues, resulting in amino acid changes that alter the electrophysiologic properties of the glutamate receptor. Previous studies showed that these amino acid changes are due to adenosine to inosine conversions in two codons resulting from adenosine deamination. Here, we describe the purification and characterization of an activity from human HeLa cells that efficiently and accurately edits GluR-B pre-mRNA at both of these sites. The purified activity contains a human homolog of the recently reported rat RED1 (rRED1) protein, a member of the family of double-stranded RNA-dependent deaminase proteins. Recombinant human RED1 (hRED1), but not recombinant dsRAD, another member of the family, efficiently edits both the Q/R and R/G sites of GluR-B RNA. We conclude that the GluR-B editing activity present in HeLa cell extracts and the recombinant hRED1 protein are indistinguishable.