Coupled in vitro transcription and translation of vesicular stomatitis virus messenger RNA.

The virion transcriptase (nucleosidetriphosphate: RNA nucleotidyltransferase, EC 2.7.7.6) of vesicular stomatitis virus was fully active when ribonucleoprotein cores from purified virions were added to cell-free protein synthesizing systems of eukaryotic origin. Synthesis of mRNA was linear for at least 3 hr and the newly synthesized viral mRNA was efficiently utilized for the synthesis of viral proteins N (nucleoprotein), NS, and M (matrix); small amounts of a putative G (glycoprotein protein precursor and several unidentified polypeptides were regularly synthesized. The ratio of the various newly synthesized viral proteins was identical after different periods of coupled mRNA and protein synthesis. Identical proteins were obtained when the cell-free protein synthesizing systems were programmed with purified VSV mRNA synthesized in vitro. No detectable L protein was synthesized, even though transcripts complementary to the complete viral genome were detectable in the mRNA preparation by hybridization.