An Influence of Modification with Phosphoryl Guanidine Combined with a 2'-O-Methyl or 2'-Fluoro Group on the Small-Interfering-RNA Effect.

Small interfering RNA (siRNA) is the most important tool for the manipulation of mRNA expression and needs protection from intracellular nucleases when delivered into the cell. In this work, we examined the effects of siRNA modification with the phosphoryl guanidine (PG) group, which, as shown earlier, makes oligodeoxynucleotides resistant to snake venom phosphodiesterase. We obtained a set of siRNAs containing combined modifications PG/2'-O-methyl (2'-OMe) or PG/2'-fluoro (2'-F); biophysical and biochemical properties were characterized for each duplex.