In Vitro TRANSCRIPTION OF A TRANSFER RNA GENE

TheEscherichia coli tRNATyr gene carried by the ϕ80psu3 + transducing phage was transcribedin vitro by DNA-dependent RNA polymerase. The enzymatically synthesized tRNATyr -like polynucleotide chains were detected by competition with purifiedE. coli 32 P-tRNATyr for specific hybridization sites on ϕ80psu3 + DNA. Analysis by sucrose gradient centrifugation showed the tRNATyr -like chains to possess a heterogeneous distribution with respect to sedimentation coefficients, with a broad peak around 8 S. The presence of the termination factor ρ during the transcription did not significantly reduce the average size of thein vitro synthesized tRNATyr -like chains.