RNA complementary to alfalfa mosaic virus RNA 4 is not translated in vitro

cDNA of the subgenomic messenger RNA (RNA 4) of alfalfa mosaic virus was ligated in both orientations into plasmids containing the bacteriophage SP 6 promoter. Upon transcription in vitro these plasmids yielded synthetic full-length complementary RNA and messenger-sense RNA. The complementary RNA contained an open reading frame of 417 nucleotides; the messenger-sense RNA encodes the virus coat protein. No translation products from the complementary RNA were detected in a wheat germ translation system, a reticulocyte lysate translation system, or Xenopus oocytes, whereas the messenger sense RNA was very active in these translation systems.