Development of peptide-oligonucleotide conjugates for regulation of small RNA function

Recently, various microRNAs (miRNAs) and endogenous small interfering RNAs (siRNAs) have been identified and play important roles in gene regulatory networks. However it is a little known about their biological functions. These small RNAs exhibit their function to form a ribonucleoprotein complex, the RISC (RNA-induced silencing complex), which modulates gene expression by translational repression. In this study, we developed a novel peptide antagonist to inhibit the RISC function. The peptide was conjugated to 2'-O-methyl oligoribonucleotides, which have a complementary sequence to the guide strand of siRNA, and regulatory effects of the peptide on RISC activity were examined. It was revealed that the peptide drastically enhanced inhibitory effects of the oligonucleotide on RISC activity. Here we demonstrate our peptide-oligonucleotide conjugate that can provide a powerful and specific way to regulate the small RNA function.