Site-specific labeling of microRNA precursors: a structure activity relationship study

Functionalized oligoribonucleotides are essential tools in RNA chemical biology. Various synthetic routes have been developed over recent years to conjugate functional groups to oligoribonucleotides. However, the presence of the functional group on the oligoribonucleotide backbone can lead to partial or total loss of biological function. The limited knowledge around the positioning of functional groups therefore represents an important hurdle for the development of oligoribonucleotide chemical tools. Here we describe a systematic investigation of site-specific labeling of pre-miRNAs to identify positions for functional groups which do not hinder their processing into active mature miRNAs.