Modified Nucleosides in RNA

Abstract

Natural and unnatural modified nucleosides play important roles in chemistry and biology. Over 100 different functional group modifications occur on natural nucleosides, which range from sugar methylations to base isomerization reactions. Unnatural modifications are also broad in their range of possible structures and applications. Both types of modifications have been incorporated site specifically into RNAs to understand their biological roles or to be used as biophysical, structure, and mechanistic probes. More recently, modified RNAs have been applied as therapeutic agents. This article summarizes the approaches toward generation of modified nucleosides and their incorporation into RNA using chemical, biochemical, or combined (semisynthesis) approaches. Some examples of applications with modified RNAs will also be discussed.