Yang J H, Sklar P, Axel R, Maniatis T
Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA.
Proc Natl Acad Sci U S A. 1997 Apr 29;94(9):4354-9. 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.
谷氨酸受体亚基B（GluR - B）前体mRNA在两个腺苷残基处发生编辑，导致氨基酸改变，进而改变谷氨酸受体的电生理特性。先前的研究表明，这些氨基酸变化是由于腺苷脱氨导致两个密码子中的腺苷转变为肌苷所致。在此，我们描述了从人HeLa细胞中纯化并鉴定出的一种活性物质，它能高效且准确地在这两个位点编辑GluR - B前体mRNA。纯化后的活性物质包含一种人类同源物，即最近报道的大鼠RED1（rRED1）蛋白，它是双链RNA依赖性脱氨酶蛋白家族的成员。重组人RED1（hRED1），而非该家族的另一个成员重组dsRAD，能高效编辑GluR - B RNA的Q/R和R/G位点。我们得出结论，HeLa细胞提取物中存在的GluR - B编辑活性与重组hRED1蛋白难以区分。
