Figure 1. Schematic representation of the ISA method used to recover infectious ZIKVs.

The entire viral genome, schematically represented in the figure, flanked respectively at the 5′ and 3′ untranslated regions by the pCMV and the HDR/SV40pA, was de novo synthesized in three double-stranded overlapping DNA fragments. Each of these was then amplified by PCR and all subgenomic products were pooled and transfected into permissive cells to generate infectious ZIKVs.