Inducing gene expression by targeting promoter sequences using small activating RNAs

Abstract

Vector-based systems comprised of exogenous nucleic acid sequences remain the standard for ectopic expression of a particular gene. Such systems offer robust overexpression, but have inherent drawbacks such the tedious process of construction, excluding sequences (e.g. introns and untranslated regions) important for gene function and potential insertional mutagenesis of host genome associated with the use of viral vectors. We and others have recently reported that short double-stranded RNAs (dsRNAs) can induce endogenous gene expression by targeting promoter sequences in a phenomenon referred to as RNA activation (RNAa) and such dsRNAs are termed small activating RNAs (saRNAs). To date, RNAa has been successfully utilized to induce the expression of different genes such as tumor suppressor genes. Here, we describe a detailed protocol for target selection and dsRNA design with associated experiments to facilitate RNAa in cultured cells. This technique may be applied to selectively activate endogenous gene expression for studying gene function, interrogating molecular pathways and reprogramming cell fate.