Sendai Virus RNA-dependent RNA Polymerase L Protein Catalyzes Cap Methylation of Virus-specific mRNA
| Autor: | Tomoaki Ogino, Kiyohisa Mizumoto, Masaki Kobayashi, Minako Iwama |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
RNA Caps
Five-prime cap DNA Complementary viruses Blotting Western RNA-dependent RNA polymerase Sodium Chloride Biology Methylation Sendai virus Biochemistry Substrate Specificity Viral Proteins chemistry.chemical_compound RNA polymerase Gene expression RNA polymerase I Humans RNA Messenger Molecular Biology Messenger RNA Dose-Response Relationship Drug Models Genetic RNA DNA-Directed RNA Polymerases Methyltransferases Cell Biology RNA-Dependent RNA Polymerase Molecular biology Protein Structure Tertiary chemistry RNA Viral Electrophoresis Polyacrylamide Gel Baculoviridae Small nuclear RNA |
| Zdroj: | Journal of Biological Chemistry. 280:4429-4435 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.m411167200 |
| Popis: | The Sendai virus (SeV) RNA-dependent RNA polymerase complex, which consists of L and P proteins, participates in the synthesis of viral mRNAs that possess a methylated cap structure. To identify the SeV protein(s) involved in mRNA cap methylation, we developed an in vitro assay system to detect mRNA (guanine-7-)methyltransferase (G-7-MTase) activity. Viral ribonucleoprotein complexes and purified recombinant L protein but not P protein exhibited G-7-MTase activity. On the other hand, mRNA synthesis in a reconstituted transcription system using purified N-RNA (N protein-genomic RNA) complex as a template required both the L and P proteins. The enzymatic properties of SeV G-7-MTase were different from those of cellular G-7-MTase. In particular, unlike cellular G-7-MTase, the SeV enzyme preferentially methylated capped RNA containing the viral mRNA 5'-end sequences (GpppApGpG-). The C-terminal part (amino acid residues 1,756-2,228) of the L protein catalyzed cap methylation, whereas the N-terminal half (residues 1-1,120) containing putative RNA polymerase subdomains did not. This is to our knowledge the first direct biochemical evidence that supports the idea that mononegavirus L protein catalyzes cap methylation as well as RNA synthesis. |
| Databáze: | OpenAIRE |
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