The inventions is based on an expression enhancer sequence derived from the RNA-2genome segment of a bipartite RNA virus, in which a target initiation site in theRNA-2 genome segment has been mutated. Deletion of appropriate start codonsupstream of the main RNA2 translation initiation can greatly increase in foreignprotein accumulation without the need for viral replication. Also providedare methods, vectors and systems, including the hyper-translatableCowpea Mosaic Virus (CPMV-HT) based protein expression system.
