title: Triplex formation with 2'-O,4'-C-ethylene-bridged nucleic acids (ENA) having C3'-endo conformation at physiological pH.
abstract: Antigenes, which are substances that inhibit gene expression by binding to double-stranded DNA (dsDNA) in a sequence-specific manner, are currently sought for the treatment of various gene-related diseases. As such antigenes, we developed new nuclease-resistant oligopyrimidine nucleotides that are partially modified with 2'-O,4'-C-ethylene nucleic acids (ENA), which are constrained in the C3'-endo conformation and can form a triplex with dsDNA at physiological pH. It was found that these oligonucleotides formed triplexes similarly to those partially modified with 2'-O,4'-C-methylene nucleic acids (2',4'-BNA or LNA), as determined by UV melting analyses, electromobility shift assays, CD spectral analyses and restriction enzyme inhibition assays. In our studies, oligonucleotides fully modified with ENA have delta torsion angle values that are marginally higher than those of 2',4'-BNA/LNA. ENA oligonucleotides present in 10-fold the amount of dsDNA were found to be favorable in forming triplexes. These results provide useful information for the future design of triplex-forming oligonucleotides fully modified with such nucleic acids constrained in the C3'-endo conformation considering that oligonucleotides fully modified with 2',4'-BNA/LNA do not form triplexes.
authors.affiliation: Exploratory Chemistry Research Laboratories, Sankyo Co. Ltd, Tokyo 140-8710, Japan. koizum@shina.sankyo.co.jp
authors.forename: Makoto
authors.initials: M
authors.lastname: Koizumi
authors.forename: Koji
authors.initials: K
authors.lastname: Morita
authors.forename: Makiko
authors.initials: M
authors.lastname: Daigo
authors.forename: Shinya
authors.initials: S
authors.lastname: Tsutsumi
authors.forename: Koji
authors.initials: K
authors.lastname: Abe
authors.forename: Satoshi
authors.initials: S
authors.lastname: Obika
authors.forename: Takeshi
authors.initials: T
authors.lastname: Imanishi
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005030:Ethylenes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009705:Nucleosides / Q000138:chemical synthesis / Q000737:chemistry; D009841:Oligonucleotides / Q000737:chemistry* / Q000378:metabolism / Q000627:therapeutic use
chemical_list: D005030:Ethylenes; D009705:Nucleosides; D009841:Oligonucleotides; C051802:triplex DNA; D004247:DNA; D004262:DNA Restriction Enzymes