[Interaction of RNA polymerase with hybrid plasmids carrying Escherichia coli threonine operon].
The RNA polymerase binding with two hybrid plasmids carrying threonine operon genes was studied. RNA polymerase binding sites were localized using nitrocellulose binding assay and electron microscopy visualization of the RNA polymerase--DNA complexes. To confirm that observed RNA polymerase binding sites are real promoters we analyzed RNA transcripts synthesized in vitro by hybridization with DNA fragments. The promoters of following genes were localized on the plasmid maps: ampicilline, threonine and RNA-primer of DNA replication. Two latter promoters bound RNA polymerase only being in the supercoiled DNA molecule. Several additional binding sites were found. The positions of some of these sites corresponded with known sites of rho-independent transcription termination.