title: Synthesis of 2'-O-[2-(N-methylcarbamoyl)ethyl]ribonucleosides using oxa-Michael reaction and chemical and biological properties of oligonucleotide derivatives incorporating these modified ribonucleosides.
abstract: To develop oligonucleotides containing new 2'-O-modified ribonucleosides as nucleic acid drugs, we synthesized three types of ribonucleoside derivatives modified at the 2'-hydroxyl group with 2-(methoxycarbonyl)ethyl (MOCE), 2-(N-methylcarbamoyl)ethyl (MCE), and 2-(N,N-dimethylcarbamoyl)ethyl (DMCE) groups, as key intermediates, via the oxa-Michael reaction of the appropriately protected ribonucleoside (U, C, A, and G) derivatives. Among them, the 2'-O-MCE ribonucleosides were found to be the most stable under basic conditions. To study the effects of the 2'-O-modification on the nuclease resistance of oligonucleotides incorporating the 2'-O-modified ribonucleosides and their hybridization affinities for the complementary RNA and DNA strands, 2'-O-MCE-ribonucleoside phosphoramidite derivatives were successfully synthesized and subjected to the synthesis of 2'-O-MCE-oligonucleotides and 2'-O-methyl-oligonucleotides incorporating 2'-O-MCE-ribonucleosides. The 2'-O-MCE-oligonucleotides and chimeric oligomers with 2'-O-MCE and 2'-O-methyl groups thus obtained demonstrated complementary RNA strands and much higher nuclease resistances than the corresponding 2'-O-methylated species. Finally, we incorporated the 2'-O-MCE-ribonucleosides into antisense 2'-O-methyl-oligoribonucleotides to examine their exon-skipping activities in splicing reactions related to pre-mRNA of mouse dystrophin. The exon-skipping assay of these 2'-O-methyl-oligonucleotide incorporating 2'-O-MCE-uridines showed better efficacies than the corresponding 2'-O-methylated oligoribonucleotide phosphorothioate derivatives.
authors.affiliation: Department of Life Science, Tokyo Institute of Technology, J2-12, 4259 Nagatsuta, Midoriku, Yokohama 226-8501, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Natsuki
authors.initials: N
authors.lastname: Okaniwa
authors.forename: Hisao
authors.initials: H
authors.lastname: Saneyoshi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Ohkubo
authors.forename: Kohji
authors.initials: K
authors.lastname: Seio
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Nagata
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Aoki
authors.forename: Shin'ichi
authors.initials: S
authors.lastname: Takeda
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Sekine
mesh_terms: D000179:Acrylates / Q000737:chemistry; D000818:Animals; D001483:Base Sequence; D016189:Dystrophin / Q000235:genetics; D005091:Exons / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D006878:Hydroxides / Q000737:chemistry; D051379:Mice; D009693:Nucleic Acid Hybridization; D009843:Oligoribonucleotides / Q000138:chemical synthesis* / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000737:chemistry; D011685:Purine Nucleotides / Q000737:chemistry; D012326:RNA Splicing; D012260:Ribonucleases / Q000378:metabolism; D013379:Substrate Specificity; D014529:Uridine / Q000737:chemistry
chemical_list: D000179:Acrylates; D016189:Dystrophin; D006878:Hydroxides; D009843:Oligoribonucleotides; D009943:Organophosphorus Compounds; D011685:Purine Nucleotides; C434331:phosphoramidite; C031356:hydroxide ion; D012260:Ribonucleases; D014529:Uridine