Translational specificity in reovirus-infected mouse fibroblasts

The specificity of protein synthesis in reovirus-infected mouse SC-1 cells was investigated, with the following results: a, extracts from infected and control cells translated saturating levels of capped globin mRNA with the same efficiency; b, infected cell extracts did not display a virus-induced increase in the capacity to translate decapped globin mRNA; c, translation of both cellular and viral messages was equally sensitive to the cap analog, 7-methylguanosine 5'-triphosphate. These findings are consistent with a previously published model (Walden, W., Godefroy-Colburn, T., and Thach, R. E. (1981) J. Biol. Chem. 256, 11739-11746) in which translation rates in reovirus-infected SC-1 cells are regulated by competition of capped host and viral mRNAs for a component of the unaltered protein synthetic system. Similar experimental results were obtained using reovirus-infected mouse L cells, with the following exceptions: a, the shutoff of host translation was far greater in L cells than in SC-1 cells; b, extracts of infected L cells were less active than controls for translation of all mRNAs tested. The reasons for the differences between SC-1 cells and L cells in their response to reovirus infection are being investigated.