Mechanisms and regulation of rna virus recombination

This review attempts to summarize the most important data concerning of molecular mechanisms and regulation of the viral recombination. Two mechanisms are responsible for RNA virus recombination, specifically replicative recombination based on replicase template switching and nonreplicative joining among fragments of viral origin. Retroviruses recombination occurs during DNA synthesis, whereby reverse transcriptase undergoes template switching between the two copackaged RNAs, However numerous questions about molecular mechanisms of RNA recombination remain unanswered. RNA recombination is one of the driving forces of genetic variability and virus evolution. But significant differences in recombination frequency were observed among various RNA viruses and retroviruses. We do not understand conclusively why the frequency of RNA recombination varies so much among RNA viruses but the data summarized in this review support the hypothesis according to which not only selection forces plays a role in the determination of the recombination rate. Numerous virus and host factors were found to affect the rate of viral RNA recombinants and the distribution of recombination breakpoints