Abstract: It has been shown that a 5' untranslated leader sequences of RNA virus non-structural genes act as enhancers of translation of mRNA. These leader sequences can be ligated upstream of an appropriate mRNA or used in the form of a cDNA expression vector. The translational enhancers are effective in many different types of expression systems, such as plant cells, bacterial cells and animal cells as well as translation systems made from these cells. Tobacco mosaic virus (TMV), turnip yellow mosaic virus (TYMV), brome mosaic virus (BMV), alfalfa mosaic virus (A1MV) and rous sarcoma virus (RSV) are examples of RNA viruses whose 5' untranslated leader sequences of non-structural genes enhance translation.

Abstract: It has been found that the 5' regions of RNA viruses act as enhancers of translation of mRNA. The omega prime (.OMEGA.') sequence of Tobacco Mosaic Virus, derivatives and portions thereof, and 5' leader sequences of other RNA viruses can be ligated upstream of an appropriate mRNA or used in the form of cDNA in an expression vector. The translational enhancers are effective in many different types of expression system, for example plant cells, bacteria, and animal cells, and also in in vitro translation.