ABSTRACT
The yeast viruses comprise an excellent model system for studies of the relationship between a host eukaryotic cell and its persistent double-stranded ribonucleic acid (dsRNA) viruses. There are dsRNA viruses of plants, bacteria, fungi, invertebrates, and vertebrates. There are dsRNA viruses that persistently infect animal cells, plant cells, and insect cells, but in the fungi persistent infection by dsRNA viruses is the rule rather than the exception. The dsRNAs of virus particles from different strains of S. cerevisiae have been investigated in several laboratories. They have been sized by a number of techniques, none as accurate as those available for dsDNAs. Suppressive sensitive strains of S. cerevisiae, when mated to killer strains, produce sensitive diploids and sensitive spores from those diploids. The resultant sensitive strains are again suppressive sensitive. Such strains no longer have M dsRNA, but rather smaller dsRNAs, also encapsidated in Saccharomyces cerevisiae viruses (ScV) particles, which are designated ScV-S.
