Site-Selective Artificial Ribonucleases and their Applications

Recent developments in artificial enzymes for site-selective scission of RNA have been reviewed, and their advantages over ribozymes are discussed. Most of previous reports involve covalent fixation of molecular scissors to sequence- recognizing moieties. However, non-covalent strategy, in which these two components are never covalently bound each other, has made remarkable progresses. When oligonucleotide bearing an acridine (site-selective activator) forms duplex with RNA substrate, the phosphodiester linkage of the RNA in front of the acridine is selectively activated and hydrolyzed by various metal ions (e.g., Lu(III). These non-covalent artificial ribonucleases are simple enough to be used for various more complicated systems. For example, tandem activator for clipping of desired fragment from long RNA substrate is obtained by attaching two acridines to an oligonucleotide. By analyzing the resultant RNA fragment with MALDI-TOFMS, the RNA substrate is accurately genotyped in terms of both single nucleotide polymorphisms (SNPs) and insertion/deletion polymorphisms (Indels).