Rolling circle amplification: A high fidelity and efficient alternative to plasmid preparation for the rescue of infectious clones

Alphaviruses (genus Alphavirus; family Togaviridae) are a medically relevant family of viruses that include chikungunya virus and Mayaro virus. Infectious cDNA clones of these viruses are necessary molecular tools to understand viral biology. Traditionally, rescuing virus from an infectious cDNA clone requires propagating plasmids in bacteria, which can result in mutations in the viral genome due to bacterial toxicity or recombination and requires specialized equipment and knowledge to propagate the bacteria. Here, we present an alternative- rolling circle amplification (RCA), an in vitro technology. We demonstrate that the viral yield of transfected RCA product is comparable to midiprepped plasmid, albeit with a slight delay in kinetics. RCA, however, is cheaper and less time-consuming. Further, sequential RCA did not introduce mutations into the viral genome, subverting the need for glycerol stocks and retransformation. These results indicate that RCA is a viable alternative to traditional plasmid-based approaches to viral rescue.