%0 Journal Article
%T Locked nucleoside analogues expand the potential of DNAzymes to cleave structured RNA targets
%A Birte Vester
%A Lykke H Hansen
%A Lars Bo Lundberg
%A B Ravindra Babu
%A Mads D S£¿rensen
%A Jesper Wengel
%A Stephen Douthwaite
%J BMC Molecular Biology
%D 2006
%I BioMed Central
%R 10.1186/1471-2199-7-19
%X We investigated how incorporation of LNA (locked nucleic acid) monomers into DNAzymes improves their ability to gain access and cleave at highly-structured RNA targets. The binding arms of DNAzymes were varied in length and were substituted with up to three LNA and ¦Á-L-LNA monomers (forming LNAzymes). For one DNAzyme, the overall cleavage reaction proceeded fifty times faster after incorporation of two ¦Á-L-LNA monomers per binding arm (kobs increased from 0.014 min-1 to 0.78 min-1).The data demonstrate how hydrolytic performance can be enhanced by design of LNAzymes, and indicate that there are optimal lengths for the binding arms and for the number of modified LNA monomers.DNAzymes function as specific endonucleases by binding to predetermined sequences in RNA and cleaving its phosphodiester backbone. The discovery that RNA-hydrolytic properties could be encoded within a DNA oligonucleotide indicated potential biotechnological applications in gene silencing. These applications might even surpass those of other oligonucleotide-based gene silencing approaches, such as antisense and RNAi technologies, that require the complicity of the cell's own nuclease systems in order to cleave RNA. However, the use of DNAzymes has been restricted by several limitations, some of which are shared with the other oligonucleotide-based technologies. For any of these approaches to be of value, the oligonucleotide must be capable of transversing the cellular membrane and avoid being inactivated by cellular nucleases long enough to find the appropriate cellular compartment where it can bind and induce cleavage at the target RNA. Modification of DNAzymes to improve their stability against cellular nucleases and their ability to bind and cleave RNA molecules would go a long way towards increasing their general applicability.The 10¨C23 DNAzyme isolated by Santoro and Joyce [1] (Fig. 1A) provides a suitable starting point for such modification and improvement. DNAzymes of this type cleave pur
%U http://www.biomedcentral.com/1471-2199/7/19