The present invention describes oligonucleotides that bind to microRNA target sites in target RNAs, such as mRNAs. The oligonucleotides of the invention may mediate RNase H degradation of the target RNA, mediate RNAi of the target RNA or prevent microRNA regulation of the target RNA. The oligonucleotides of the invention are useful e.g. as research tools for studying microRNA:mRNA interactions and for therapeutic development. The present invention also describes methods of identifying microRNA target sites, methods of validating microRNA target sites, methods of identifying oligonucleotides of the invention and methods of modulating the activity of a target RNA using the oligonucleotides of the invention.
