Specific and nonspecific inhibition of transcription by DNA, PNA, and phosphorothioate promoter analog duplexes

DNA duplexes analogous to the promoters for SP6 or T7 RNA polymerase inhibit transcription with exquisite selectivity. By contrast, phosphorothioate oligomers inhibit nonselectively, and peptide nucleic acid (PNA) duplexes and PNA:DNA heteroduplexes do not inhibit at all. The absence of recognition of proteins by PNAs may prove to be a substantial advantage for their use as anti-sense agents and nucleic acid probes.