title: Recognition of alternating oligopurine/oligopyrimidine tracts of DNA by oligonucleotides with base-to-base linkages.
abstract: A new concept is presented to design and synthesize modified oligonucleotides in order to extend the range of double-helical DNA sequences that can be recognized by oligonucleotides via triple helix formation. The DNA target is composed of adjacent oligopurine.oligopyrimidine domains where the oligopurine sequences alternate on the two DNA strands. Canonical (C,T)-motif triple helices are formed with each oligopurine.oligopyrimidine domain of the target sequence. The two third-strand oligonucleotides were joined together via an appropriate linker between the two terminal bases with either a 3'-3' or a 5'-5' polarity. Molecular modeling was used to predict the optimal length of the linker bridging two terminal bases. The interaction of DNA with such a modified oligonucleotide containing a C3'-3'U linkage was studied by thermal dissociation, footprinting, and gel retardation experiments. They provide experimental evidence that the oligonucleotide does form a switched triple helix on this extended DNA target sequence. The binding of the so-called "switch oligonucleotide" is enhanced as compared to the two unlinked parental oligonucleotides which form triple helices with each oligopurine.oligopyrimidine domain of the target sequence.
authors.affiliation: Laboratoire de Biophysique, INSERM U201, CNRS URA481, Muséum National d'Histoire Naturelle, Paris, France.
authors.forename: B W
authors.initials: BW
authors.lastname: Zhou
authors.forename: C
authors.initials: C
authors.lastname: Marchand
authors.forename: U
authors.initials: U
authors.lastname: Asseline
authors.forename: N T
authors.initials: NT
authors.lastname: Thuong
authors.forename: J S
authors.initials: JS
authors.lastname: Sun
authors.forename: T
authors.initials: T
authors.lastname: Garestier
authors.forename: C
authors.initials: C
authors.lastname: Hélène
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D018983:DNA Footprinting; D066298:In Vitro Techniques; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis / Q000737:chemistry* / Q000235:genetics; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D009838:Oligodeoxyribonucleotides; D004247:DNA