title: Synthesis of novel siRNAs having thymidine dimers consisting of a carbamate or a urea linkage at their 3' overhang regions and their ability to suppress human RNase L protein expression.
abstract: In order to examine the effect of modifications at the 3' overhang regions of short interfering RNAs (siRNAs) on their gene-silencing activities, we designed and synthesized novel siRNAs having thymidine dimers consisting of a carbamate or a urea linkage at their 3' overhang regions. Suppression of human RNase L protein expression by these siRNAs was analyzed by immunoblot with RNase L-specific antibody. It was found that, at 24 h post-transfection, the modified siRNAs having the thymidine dimers with the carbamate and urea linkage suppress the protein expression 78 and 37 times more efficiently than that with the natural phosphodiester linkage, respectively. Furthermore, the siRNA containing the carbamate linkage was 37 times more resistant to nucleolytic degradation by snake venom phosphodiesterase than the siRNA consisting of the natural phosphodiester linkage. Thus, the RNA duplexes having the thymidine dimers with the carbamate or urea linkage at their 3' overhang regions will be promising candidates for novel siRNA molecules to down-regulate protein expression.
authors.affiliation: Department of Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Ueno
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Naito
authors.forename: Koshi
authors.initials: K
authors.lastname: Kawada
authors.forename: Aya
authors.initials: A
authors.lastname: Shibata
authors.forename: Hye-Sook
authors.initials: HS
authors.lastname: Kim
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Wataya
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kitade
mesh_terms: D002219:Carbamates / Q000737:chemistry*; D019281:Dimerization; D004722:Endoribonucleases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D006801:Humans; D009691:Nucleic Acid Denaturation; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry; D034741:RNA, Small Interfering / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D012910:Snake Venoms / Q000201:enzymology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013936:Thymidine / Q000737:chemistry*; D014407:Tumor Cells, Cultured; D014508:Urea / Q000737:chemistry*
chemical_list: D002219:Carbamates; D034741:RNA, Small Interfering; D012910:Snake Venoms; D014508:Urea; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease; D010727:Phosphoric Diester Hydrolases; D013936:Thymidine