title: Study of modification pattern-RNAi activity relationships by using siRNAs modified with 4'-thioribonucleosides.
abstract: A detailed study of the modification pattern-RNAi activity relationships by using siRNAs that are modified with 4'-thioribonucleosides has been carried out against photinus luciferase and renilla luciferase genes in cultured mammalian NIH/3T3, HeLa, and MIA PaCa-2 cell lines. When the photinus luciferase gene was targeted, all of the modified siRNAs showed activity equal to, or less than the unmodifed siRNA. In contrast, all modified siRNAs that have a similar modification pattern showed activity equal to or much higher than the unmodified siRNA when tested with the renilla luciferase gene. These results indicated that siRNAs such as RNA33 and RNA53, which each have four residues of the 4'-thioribonucleoside unit on both ends of the sense strand and four residues on the 3'-end of the antisense strand, were the most effective. Accordingly, we succeeded in developing modified siRNAs that have the greatest number of 4'-thioribonucleosides without loss of RNAi activity, and that exhibit potent RNAi activity against two target genes in three different cell lines. Our findings also indicate the significance of target sequences and cell lines when RNAi activity is compared with that of the unmodified siRNA.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Hoshika
authors.forename: Noriaki
authors.initials: N
authors.lastname: Minakawa
authors.forename: Aki
authors.initials: A
authors.lastname: Shionoya
authors.forename: Keiko
authors.initials: K
authors.lastname: Imada
authors.forename: Naoki
authors.initials: N
authors.lastname: Ogawa
authors.forename: Akira
authors.initials: A
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D002460:Cell Line; D048888:Fireflies / Q000201:enzymology; D049409:Luciferases, Firefly / Q000235:genetics / Q000378:metabolism; D051379:Mice; D015394:Molecular Structure; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000737:chemistry* / Q000235:genetics*; D012265:Ribonucleotides / Q000737:chemistry* / Q000235:genetics*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D034741:RNA, Small Interfering; D012265:Ribonucleotides; D013438:Sulfhydryl Compounds; D049409:Luciferases, Firefly