Cloning of the chicken RNA polymerase I promoter and use for reverse genetics of influenza a viruses in avian cells

Reverse genetics techniques to rescue influenza viruses have thus far been based on the use of a human polymerase I (Poll) promoter to direct the synthesis of the eight viral RNAs. They can only be used on cells from primate origin due to the species specificity of the Poll promoter. Here we report the cloning of the chicken Poll promoter sequence and the generation of recombinant influenza virus upon transfection of bidirectional PoII/PoIII plasmids in avian cells. Potential contributions of this new reverse genetics system in the fields of influenza virus research and influenza vaccine production are discussed.