Viral proteins formed in a cell-free rabbit reticulocyte system programmed with RNA from a temperature-sensitive mutant of Sindbis virus.
Viral messenger RNA was isolated from BHK cells infected with a temperature-sensitive mutant of Sindbis virus and was further purified using an oligo(dT) column. Addition of this mRNA cell-free extracts from rabbit reticulocytes led to formation of discrete authentic viral capsid protein when the reaction was performed at 29 C. However, this same protein-synthesizing system failed to make discrete viral capsid when incubated with the viral RNA at 39 C. Instead, larger-molecular-weight polypeptides that contained the viral capsid peptide sequences were produced. The inability to make a separate viral capside protein in vitro at elevated temperatures by the mRNA from this mutant exactly mimics the phenotype of this ts mutant in viral-infected cells. Three mechanisms are discussed that might account for a temperature-sensitive release of capsid. One of these is based on a model in which there are multiple sites for initiation of translation of polypeptides on a polycistronic viral mRNA.
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001345:Autoradiography; D002474:Cell-Free System; D002501:Centrifugation, Zonal; D066298:In Vitro Techniques; D009154:Mutation; D010455:Peptides / Q000032:analysis; D014176:Protein Biosynthesis / Q000187:drug effects; D012333:RNA, Messenger; D012367:RNA, Viral; D011817:Rabbits; D012156:Reticulocytes; D012845:Sindbis Virus; D013462:Sulfur Radioisotopes; D013696:Temperature; D014764:Viral Proteins / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D010455:Peptides; D012333:RNA, Messenger; D012367:RNA, Viral; D013462:Sulfur Radioisotopes; D014764:Viral Proteins