The present invention relates to a methodology for the generation of infectious ribonucleoparticles (RNPs) of negative-strand RNA viruses, and in particular of non-segmented negative-strand RNA viruses in yeast, especially in budding yeast. Accordingly, the patent application relates to a recombinant yeast strain suitable for the rescue of infectious non-segmented negative-strand RNA virus particles or infectious virus-like particles. The invention also relates to the use of the recombinant yeast to prepare vaccine seed and to the use of the produced RNPs or RNPs-like to prepare vaccine formulations. It also concerns the use of the recombinant yeast for the screening of libraries of DNA.
