Interaction Of Escherichia-Coli Rna-Polymerase With The Genome Of Proteus-Mirabilis Phage 5006m

The genome of Proteus mirabilis phage 5006M has several binding sites for Escherichia coli RNA polymerase, as evidenced by the retention on nitrocellulose filters of restriction endonuclease Eco R1 fragments A-F. Ternary complexes are formed on these fragments except for fragments A and F, yet the latter is the strongest binder of RNA polymerase. Possible explanations for this discrepancy are presented. Transcriptional R-loops were observed on the intact genome. These observations are compared with the partial denaturation characteristics of the phage genome. In spite of quantitative discrepancies, the data are qualitatively in mutual agreement. The observed in vitro RNA synthesis is interpreted in terms of initiation sites (promoters) and the pattern of transcription appears similar to that of other phage genomes. Two strong promoters divide the molecule into leftward and rightward transcriptional regions and the left arm is transcriptionally less active than the right arm of the genome.