Establishment of Vector System Harboring Duck RNA Polymerase I Promoter for Avian Influenza Virus

Reverse genetics (RG) systems are extensively utilized to investigate the characteristics of influenza viruses and develop vaccines, predominantly relying on human RNA polymerase (pol I). However, the efficiency of RG systems for avian-origin influenza viruses may be compromised due to potential species-specific interactions of RNA pol I. In this study, we report the polymerase activities of the duck RNA pol I promoter in avian cells and the generation of recombinant avian-derived influenza viruses using a novel vector system containing the duck RNA pol I promoter region to enhance the rescue efficiency of the RG system in avian cells. Initially, we explored a putative duck promoter region and identified the optimal size to improve the existing system. Subsequently, we established an RG system incorporating the duck RNA pol I promoter and compared its rescue efficiency with the human pol I system by generating recombinant influenza viruses in several cell lines. Notably, the 250bp duck RNA pol I promoter demonstrated effective functionality in avian cells, exhibiting higher polymerase activity in a minigenome assay. The newly constructed RG system was
significantly improved, enabling the rescue of influenza viruses in 293T, DF-1, and CCL141 cells. Furthermore, HPAI viruses were successfully rescued in DF-1 cells, a result that had not been achieved in previous experiments. In conclusion, our novel RG system harboring duck RNA pol I offers an additional tool for researching influenza viruses and may facilitate the development of vaccines for poultry.

Yunyueng Jang , Yoon-Gi Baek, Yu-Na Lee, Ra Mi Cha, Min-Ji Park, and Youn-Jeong Lee Animal and Plant Quarantine Agency

Diagnostics, vaccination, or other mitigation strategies for poultry and wildlife