Purification of cowpea mosaic virus RNA replication complex: Identification of a virus-encoded 110,000-dalton polypeptide responsible for RNA chain elongation
AUTOR(ES)
Dorssers, Lambert
RESUMO
An endogenous cowpea mosaic virus (CPMV) RNA-protein complex (CPMV replication complex) capable of elongating in vitro preexisting nascent chains to full-length viral RNAs has been solubilized from the membrane fraction of CPMV-infected cowpea leaves using Triton X-100 and purified by Sepharose 2B chromatography and glycerol gradient centrifugation in the presence of Triton X-100. Analysis of the polypeptide composition of the complex by NaDod-SO4/PAGE and silver staining revealed major polypeptides with molecular masses of 110, 68, and 57 kilodaltons (kDa), among which the 110-kDa polypeptide was consistently found to cosediment precisely with the RNA polymerase activity. Using antisera to specific viral proteins, we found the 110-kDa polypeptide to be the only known viral polypeptide associated with the RNA replication complex, the 68- and 57-kDa polypeptides being most probably host-specific. The host-encoded 130-kDa monomeric RNA-dependent RNA polymerase, which is known to be stimulated in CPMV-infected cowpea leaves, did not copurify with the virus-specific RNA polymerase complex. Our results dispute the hypothesis that plant viral RNA replication may be mediated by the RNA-dependent RNA polymerase of uninfected plants. We tentatively conclude that the 110-kDa polypeptide encoded by the bottom component RNA of CPMV constitutes the core of the CPMV RNA replication complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=345414Documentos Relacionados
- Isolation and characterization of a variant of mouse plasmacytoma J558 synthesizing a 110,000-dalton immunoglobulin heavy chain and of secondary variants synthesizing either a 55,000-dalton or an 80,000-dalton immunoglobulin heavy chain: possible implications.
- Virus-encoded RNA helicases.
- Different half-lives of the carbohydrate and protein moieties of a 110,000-dalton glycoprotein isolated from plasma membranes of rat liver.
- Cowpea Mosaic Virus-Encoded Protease Does Not Recognize Primary Translation Products of M RNAs from Other Comoviruses
- Evidence That the 32,000-Dalton Protein Encoded by Bottom-Component RNA of Cowpea Mosaic Virus is a Proteolytic Processing Enzyme