Abstract
In vitro transcription of RNA message on K174 replicative circular DNA was studied. Results are summarized as follows: During the transcription, a double-strand DNA and RNA hybrid could be detected. An RNase-resistant structure was combining the template DNA and synthesized RNA. This RNase-resistant structure moved along the DNA and existed at the region where polyrlbonucleotide chains grew. A portion of RNA synthesized was polycistronic as judged by its sedimentation constant. A model for the mechanism of genetic transcription in vitro was proposed.