COMPLEMENTATION BETWEEN TEMPERATURE-SENSITIVE MUTANTS OF POLIOVIRUS

Conditional lethal mutants of poliovirus type 1 (Mahoney) were generated by treatment with the mutagen hydroxylamine. Temperature-sensitive mutants were selected by the replica plating technique at temperatures of 33°C (permissive) and 39°C (restrictive). New mutants were generated to achieve a larger population of mutants and also to generate additional RNA- mutants in this population. These mutants were characterized by two criteria: RNA synthesis and thermal stability. RNA synthesis is measured by the accumulation of labeled uridine incorporation into trichloroacetic acid (TCA) insoluble material. The thermal stability is determined by the difference in plaque forming units before and after treatment of the virion at 45°C. Complementation co-infections (5 MOI for each virus stock) were analyzed for the presence of the 150S virion particle of poliovirus after sedimentation through a linear sucrose gradient. Complementation is observed between RNA(+) mutants v.s. RNA(-) mutants, and between two RNA(-) mutants, but not between two RNA(+) mutants. Although reciprocal complementation has not been documented in this study some speculation on complementation is presented in this thesis