[Circular transcription map of the plasmid pBR322].

The plasmid pBR322 transcription in the isolated E. coli DNA-dependent RNA-polymerase system was studied. Transcription regions as well as transcripts orientation were defined using both the technique of "criss-cross" hybridization and the annealing of RNA-products with L- and H-strands of plasmid. Summing up obtained data together with available data on promoter localization a circular transcription map of plasmid pBR322 was constructed. Effects of heparin, ion strength and E. coli S-30 system on in vitro transcripts were also studied. The 110-long RNA transcript synthesized in Ori region of pBR322 was found to be the most sensitive to all these factors. RNA-transcripts obtained in in vitro system are able to direct protein synthesis in cell-free S-30 system.