We investigated the effect of left-handed Z-DNA on transcription by bacteriophage T7 RNA polymerase in vitro and, surprisingly, found that the enzyme can efficiently utilize a template containing a stretch of lefthanded DNA close to the promoter. Analysis of transcription products revealed that only a small fraction of elongating polymerases abort transcription either at the promoter proximal or at the distal B-to-Z junction and, even less frequently, within the stretch of lefthanded DNA. Our results indicate that, unlike E.coli RNA polymerase (ref. 1,2), T7 RNA polymerase can utilize a template with a CG stretch in an alternate conformation. In contrast, polymerases are completely blocked at the promoter proximal junction by a monoclonal antibody directed against Z-DNA. This blockage remains stable over a remarkable time, even when negative supercoiling is released by linearization of the template. Together with our recent finding of transcription-induced formation of Z-DNA (3), our data provide an example for a possible auto-regulatory mechanism that employs a change in DNA conformation. © 1991 Oxford University Press.
CITATION STYLE
Dröge, P., & Pohl, F. M. (1991). The influence of an alternate template conformation on elongating phage T7 RNA polymerase. Nucleic Acids Research, 19(19), 5301–5306. https://doi.org/10.1093/nar/19.19.5301
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