Specific Sindbis virus-coded function for minus-strand RNA synthesis

D L Sawicki, S G Sawicki, S Keränen, L Kääriäinen
1981 Journal of Virology  
The synthesis of minus-strand RNA was studied in cell cultures infected with the heat-resistant strain of Sindbis virus and with temperature-sensitive (ts) mutants belonging to complementation groups A, B, F, and G, all of which exhibited an RNA-negative (RNA-) phenotype when infection was initiated and maintained at 390C, the nonpermissive temperature. When infected cultures were shifted from 28°C (the permissive temperature) to 39°C at 3 h postinfection, the synthesis of viral minus-strand
more » ... ceased in cultures infected with ts mutants of complementation groups B and F, but continued in cultures infected with the parental virus and mutants of complementation groups A and G. In cultures infected with tsll of complementation group B, the synthesis of viral minusstrand RNA ceased, whereas the synthesis of 42S and 26S plus-strand RNAs continued for at least 5 h after the shift to 39°C. However, when tsll-infected cultures were returned to 280C 1 h after the shift to 39°C, the synthesis of viral minus-strand RNA resumed, and the rate of viral RNA synthesis increased. The recovery of minus-strand synthesis required translation of new proteins. We conclude that at least one viral function is required for alphavirus minus-strand synthesis that is not required for plus-strand synthesis. In cultures infected with ts6 of complementation group F, the syntheses of both viral plus-strand and minus-strand RNAs were drastically reduced after the shift to 390C. Since ts6 failed to synthesize both plus-strand and minus-strand RNAs after the shift to 348 on May 9, 2020 by guest http://jvi.asm.org/ Downloaded from SINDBIS VIRUS MINUS-STRAND MUTANT 349 sensitive (ts) mutant of the heat-resistant strain of SIN (SIN HR) that selectively ceased minVsstrand syntheis upon shifting to the nonpermissive temperature. MATERIALS AND METHODS Cell cultures. Secondary cultures of chicken em-
doi:10.1128/jvi.39.2.348-358.1981 fatcat:lt2ecgpsnvarzcigggupstic2y