siRNA Modified with 2'-Deoxy-2'-C-methylpyrimidine Nucleosides

Chembiochem. 2018 Jul 4;19(13):1409-1413. doi: 10.1002/cbic.201800077. Epub 2018 May 30.

Abstract

(2'S)-2'-Deoxy-2'-C-methyluridine and (2'R)-2'-deoxy-2'-C-methyluridine were incorporated in the 3'-overhang region of the sense and antisense strands and in positions 2 and 5 of the seed region of siRNA duplexes directed against Renilla luciferase, whereas (2'S)-2'-deoxy-2'-C-methylcytidine was incorporated in the 6-position of the seed region of the same constructions. A dual luciferase reporter assay in transfected HeLa cells was used as a model system to measure the IC50 values of 24 different modified duplexes. The best results were obtained by the substitution of one thymidine unit in the antisense 3'-overhang region by (2'S)- or (2'R)-2'-deoxy-2'-C-methyluridine, reducing IC50 to half of the value observed for the natural control. The selectivity of the modified siRNA was measured, it being found that modifications in positions 5 and 6 of the seed region had a positive effect on the ON/OFF activity.

Keywords: deoxymethylpyrimidine bases; nucleosides; siRNA; stability; structure-activity relationships.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Enzyme Assays
  • HeLa Cells
  • Humans
  • Inhibitory Concentration 50
  • Luciferases, Renilla / genetics
  • RNA Stability
  • RNA, Small Interfering / chemical synthesis
  • RNA, Small Interfering / chemistry*
  • RNA, Small Interfering / genetics
  • Renilla / enzymology
  • Stereoisomerism
  • Temperature
  • Uridine / analogs & derivatives*
  • Uridine / chemistry

Substances

  • (2'S)-2'-deoxy-2'-C-methyluridine
  • RNA, Small Interfering
  • Luciferases, Renilla
  • Uridine