Hybridization of a complementary ribooligonucleotide to the transcription start site of the lacUV-5-Escherichia coli RNA polymerase open complex. Potential for gene-specific inactivation reagents.

An ribooligonucleotide, UGGAA, complementary to the template strand of the lacUV-5 promoter can hybridize to the transcription "bubble" of the open complex formed by Escherichia coli RNA polymerase. Its site-specific binding, measured by gel retardation, enzyme inhibition, and chemical nuclease footprinting, is dependent on catalysis by RNA polymerase and the sequence of the hybridizing ribooligonucleotide. When UGGAA is linked to the chemical nuclease 1,10-phenanthroline copper, site-specific scission of the template strand of the transcriptionally active gene is observed. The formation of single-stranded DNA at transcription start sites by RNA polymerases provides a target for antigene strategies.