The present invention relates to a recombinant viral nucleic acid selected
from a (+) sense, single stranded RNA virus possessing a native
subgenomic promoter encoding for a first viral subgenomic promoter, a
nucleic acid sequence that codes for a viral coat protein whose
transcription is regulated by the first viral subgenomic promoter, a
second viral subgenomic promoter and a second nucleic acid sequence whose
transcription is regulated by the second viral subgenomic promoter. The
first and second viral subgenomic promoters of the recombinant viral
nucleic acid do not have homologous sequences relative to each other. The
recombinant viral nucleic acid provides the particular advantage that it
systemically transcribes the second nucleic acid in the host. Host
organisms encompassed by the present invention include procaryotes and
eucaryotes, particularly animals and plants. The present invention also
relates to viruses containing the viral vectors which are infective,
production cells which are capable of producing the viruses or parts
thereof, a host infected by the viruses of the invention, the gene
products produced by expression of the viral nucleic acids and a process
for the production of a desired product by growing the infected hosts.