RECOMBINATION BETWEEN SINDBIS VIRUS RNAS

The Sindbis virus RNA genome is divided into two modules-one coding fo r the nonstructural protein genes and the other coding for the structu ral protein genes. In our studies of recombination, the two parental R NAs were defective in different modules. Analysis of the recombinant R NAs demonstrated that the parental RNAs each contributed its intact mo dule and that the crossovers occurred within the defective modules. Th e recombinational events giving rise to infectious virion RNAs could c reate deletions, rearrangements or insertions as long as they occurred outside of the functional module. These crossovers produced RNA genom es that contained two functional subgenomic RNA promoters.