Synthesis of 3′-S-Phosphorothiolate Oligonucleotides for their Potential Use in RNA Interference

Abstract

The potency of RNA interference (RNAi) undoubtedly can be improved through chemical modifications to the small interfering RNAs (siRNA). By incorporation of the 3'-S-phosphorothiolate modification into strands of RNA, it is hoped that specific regions of a siRNA duplex can be stabilised to enhance the target binding affinity of a selected antisense strand into the activated RNA-induced silencing complex (RISC*). Oligonucleotides composed entirely of this modification are desirable so unconventional 5' --> 3' synthesis is investigated, with initial solution-phase testing proving successful. The phosphoroamidite monomer required for solid-phase synthesis has also been produced.

Small interfering RNA therapy in cancer: mechanism, potential targets, and clinical applications

“…Asymmetric 5 ′ modification of siRNA duplexes can also be useful for controlling targeting specificity [31] . By incorporation of the 3 ′ -S -phosphorothiolate modification into the strands of RNA, the specific regions of a siRNA duplex can be stabilized to enhance the target-binding affinity of a selected antisense strand into the activated RISC complex [32] . An additional benefit of modifying siRNA is the avoidance of interferon induction, which is a common side effect of siRNA therapy [30,33] .…”

Polymer supported synthesis of aminooxyalkylated oligonucleotides, and some applications in the fabrication of microarrays

“…The stability of the constructed microarrays was also evaluated by spotting the microslides in a similar way at pH 6 and 9, and then subjecting them to washings with the washing buffer of different pHs (7)(8)(9) at ambient temperature. The microslides were scanned, after usual washings and drying, under a laser scanner.…”

“…In order to study the effect of pH on immobilization of aminooxyalkylated oligomers on epoxylated glass slides, the attachment of probe was carried out at different pH (4)(5)(6)(7)(8)(9)(10)(11). A labeled oligomer, TET-d(TTC GTC ATC AAG TAG TTC CT)-OPO 3 -CH 2 CH(OH)-CH 2 NHCOCH 2 ONH 2, was dissolved in reaction buffers having different pH and spotted (0.5 ll) onto epoxylated glass slides at a concentration of 1 lM using a pipettmen followed by overnight incubation at 45°C.…”

“…The technology allows highly parallel throughput processing and screening of different biological samples (e.g., mRNA, cDNA and proteins). [7][8][9][10][11][12][13][14][15] DNA microarrays are mostly based on hybridization of targets with double-stranded DNA or single-stranded oligonucleotides (probes) immobilized on a polymer support (usually glass), followed by detection by a scanning process. Of the two established methods, viz., on-chip synthesis and deposition method, the latter is the preferred route for the preparation of oligonucleotide microarrays for routine applications, as it offers flexibility in respect of different chemistries for attachment of probes on a surface of choice.…”

A strategy toward the synthesis of C13-oxidized cembrenolides

“…Removal of the extraneous silyl group was achieved using TEA-buffered HF reagent 22 under microwave irradiation conditions. This treatment afforded cleanly diols 23a and 23b in 91% average yield.…”