RNA interference expression vectors based on miRNAs and RNA splicing

Abstract

RNA interference (RNAi) has emerged as a powerful tool in basic research and therapeutics by silencing the expression of specific target genes. RNAi occurs naturally within cells to regulate gene expression at the post-transcriptional level. The development of reliable RNAi vectors encoding artificial and natural miRNAs would be useful tools for many RNAi applications. Here, we describe two new RNAi vectors, designated pSM155 and pSM30, that take into consideration of miRNA processing and RNA splicing by placing the miRNA-based artificial miRNA expression cassettes inside of synthetic introns. These vectors significantly improved the expression of a co-expressed enhanced green fluorescent protein (EGFP) marker and also provide a simplified cloning method. We discuss the advantages of these vectors, their potential applications, and concerns in using miRNA-based vectors.