RECRUITMENT OF TRANSCRIPTION FACTORS TO THE TARGET SITE BY TRIPLEX-FORMING OLIGONUCLEOTIDES

Triplex-forming oligonucleotides (TFOs) are generally designed to inhi bit transcription or DNA replication but can be used for more diverse purposes, Here we have designed a hairpin-TFO able to recruit transcri ption factors to a target DNA, The designed oligonucleotide contains a tripler-forming sequence, linked through a nucleotide loop to a doubl e-stranded hairpin including the SRE enhancer of the c-fos gene promot er, We show here that this oligonucleotide can specifically recognise its DNA target at physiological salt and pH conditions, The stability of the tripler formed under these conditions is very high: >90% of the tripler remains intact after 24 h of incubation. Bound to the double- stranded target DNA, the oligonucleotide retains its ability to intera ct specifically with transcription factors, recruiting them to the pro ximity of the target DNA. Our results suggest that this type of oligon ucleotide may prove useful in the design of new tools for artificial m odulation of gene expression.