Coupling of killer virus transcription with translation in yeast cell-free extracts.

The cytoplasmically inherited killer virus of Saccharomyces cerevisiae expresses its dsRNA genome via apparently uncapped viral transcripts produced in the cytoplasm of infected cells. Virions of this naturally temperature-sensitive virus can be added to cell-free translational extracts of uninfected yeast cells resulting in a reaction in which viral transcription and translation are coupled at 15 degrees C in vitro. In this reaction nucleotides are incorporated into full-length transcripts of the M and L-A dsRNA segments, with lower levels of incorporation into genomic RNA. In addition, incorporation of nucleotides is observed into a smaller RNA species showing no sequence relatedness to M or L-A.