Nucleic Acids Research, 1979, Vol. 6, No. 2 507-524
© 1979
Articles |
The interaction of RNA polymerase II from wheat with supercoiled and linear plasmid templates
Departments of Biophysics and Biochemistry, Searle Research Laboratories Lane End Road, High Wycombe, HP12 4HL, UK
Received December 5, 1978. Interactions between a plant RNA polymsrase II and ColE1 based plasmid DNA templates have been studied. Gel electrophoresis indicates that the enzyme binds to both supercoiled and linear species. Using the totally double stranded pN89/SmaI fragment it is shown that transcription of completely base paired DNA is ten-fold lower than that of denatured or supercoiled plasmid, and reflects the presence of fewer initiation sites. A small proportion of the transcript remains tightly bound to supercoiled templates. 3' oligodeoxycytidine extensions on pM89/SmaI serve to promote transcription of the linear double stranded form. Using restriction kinetics it is shown that there is a small enhancement of polymerase binding at the pM89 tetracycline promoter, but that the selectivity of binding at this locus is lower than for the natural bacterial polymerase.