Translation and processing of mouse hepatitis virus virion RNA in a cell-free system.

摘要: The first event after infection with mouse hepatitis virus strain A59 (MHV-A59) is presumed to be the synthesis of an RNA-dependent RNA polymerase from input genomic RNA. and processing this putative ploymerase protein was studied in a cell-free translation system utilizing 60S MHV-A59 virions. polypeptide products reaction included two major species 220 28 kilodaltons. Kinetics experiments indicated that both p220 p28 appeared 60 min incubation synthesized initially as N-terminal portion larger precursor protein. When were labeled N-formyl(/sup 35/S)methionyl-tRNA/sub i/, predominant radioactive product, confirming its location within Translation presence protease inhibitors leupeptin ZnCl/sub 2/ resulted disappearance appearance new protein, p250. This which approached maximal size predicted for RNA, not routinely detected absence even under conditions optimized elongation proteins. Subsequent chelation partial cleavage themore » reappearance p28. One-dimensional peptide mapping Staphylococcus aureus V-8 confirmed precursor-product relationship p250 results show MHV virion like many other viral RNAs, translated into large polyprotein, cleaved soon smaller, presumably functional marked contrast proteins, minimal proteolytic occurs.« less