Translation of poliovirus RNA in vitro: Detection of two different initiation sites
| Autor: | Ellie Ehrenfeld, M.L. Celma |
|---|---|
| Rok vydání: | 1975 |
| Předmět: |
Transcription
Genetic Biology medicine.disease_cause chemistry.chemical_compound Structural Biology Polysome medicine Protein biosynthesis Magnesium Molecular Biology Messenger RNA Methionine Poliovirus RNA Translation (biology) Molecular biology Peptide Fragments Molecular Weight Messenger RNP Kinetics chemistry Pronase Protein Biosynthesis Potassium RNA Viral HeLa Cells |
| Zdroj: | Journal of Molecular Biology. 98:761-780 |
| ISSN: | 0022-2836 |
| Popis: | A cell-free system from poliovirus-infected HeLa cells, which initiates and synthesizes viral proteins, has been characterized. Replication of endogenous viral RNA occurs concomitantly with protein synthesis, and newly synthesized RNA appears to associate functionally with polysomes. Endogenous host cell messenger RNA is not translated by the cell-free system; only initiation of viral polypeptides can be detected. The incorporation of formyl-[35S]methionine into the amino terminus of newly synthesized polypeptides revealed the production of two labeled tryptic peptides, originating from two different initiation sites. Purified exogenous poliovirus RNA is translated in preincubated uninfected cell extracts, and is also shown to initiate at two sites, resulting in the formation of the same two tryptic peptides. The relative proportion of each initiation is highly dependent upon small variations in the magnesium concentration during protein synthesis, with individual optima at 2 m m and 3·5 m m . The results show that both purified poliovirus RNA and endogenous messenger ribonucleoprotein contain two sites capable of initiating protein synthesis. The possible significance of double initiation for poliovirus replication is discussed. |
| Databáze: | OpenAIRE |
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