Development of the reverse genetics system for emerging atypical porcine pestivirus using in vitro and intracellular transcription systems.

Atypical porcine pestivirus (APPV) is a novel pestivirus causing congenital tremor (CT) type AII in piglets and exhibiting a broad geographical distribution. Lack of an operating system for the viral genome is one of bottlenecks which restrict further research on pathogenesis and gene functions of APPV. Reverse genetics system (RGS) is a feasible solution to this bottleneck problem, but, to-date, no RGSs have been developed for APPV. Here, for the first time, recombinant APPV CH-GD2017 were rescued using in vitro and intracellular transcription systems and the virons were observed via transmission electron microscopy. As the process of in vitro transcription is time-consuming and inefficient, a full-length cDNA clone in an intracellular transcription was further constructed using an RNA polymerase II system. Then, the rescued virus was identified via RT-PCR detection, indirect immunofluorescent assay, and transmission electron microscopy. Development of the RGS for APPV will provide an important tool for further research on this newly emerging pathogen.