mRNA amplification system by viral replicase in transgenic plants

Abstract
We have constructed transgenic tobacco plants (M1×2‐FCP2IFN plants) expressing viral RNA replication genes of brome mosaic virus (BMV) and BMV RNA3 derivative (FCP2IFN) carrying the human gamma Interferon (IFN‐γ) gene. In M1×2‐FCP2IFN plants the RNA3 derivative expressed from the integrated cDNA was replicated and subgenomic RNA (i.e. mRNA of IFN‐γ) was produced by BMV replicase. The accumulation level of the mRNA of IFN‐γ was approximately 5‐fold higher than that by the cauliflower mosaic virus (CaMV) 35S RNA promoter. In addition IFN‐γ accumulated in M1×2‐FCP2IFN plants.