An improved method for infectious bursal disease virus rescue using RNA polymerase II system

Reverse genetics system is an excellent platform to research the construction and function of viruses. Genome modification, such as gene recombination, mosaicism, and mutation may interfere with replication, assembly and release of viruses. An efficient, convenient and economical method of virus rescue is undoubtedly required for elevating the efficiency of rescuing crippled virus. In this study, we developed a method to rescue infectious bursal disease virus (IBDV) using RNA polymerase II. The genome of IBDV Gt strain, flanked by hammerhead ribozyme and hepatitis delta ribozyme sequences, were cloned downstream of the cytomegalovirus enhancer and the beta chicken actin promoter of the vector pCAGGS. Through direct transfection in various cell lines, IBDV could be rescued efficiently. The RNA polymerase II-based reverse genetics system is efficient, stable, convenient, and fit to various cells. The system not only provides the basis of the gene function research of IBDV, but is also useful for reverse genetics research of other birnaviridae viruses.