Light-activated oligonucleotides for controlling gene expression

INOR 146

Ivan J. Dmochowski, ivandmo@sas.upenn.edu, Department of Chemistry, University of Pennsylvania, 231 South 34th St., Philadelphia, PA 19104-6323
Our lab has created light-activated oligonucleotides that make it possible to control gene expression in leukemia cells and zebrafish embryos with high spatial and temporal resolution. This requires us to control DNA and RNA hybridization using a single photoactive moiety. For example, hybridization of an antisense oligodeoxynucleotide (asODN) to a target mRNA can inhibit translation by sterically blocking the ribosome or recruiting endogenous ribonucleases. Light-activated DNA hairpins were synthesized by covalently attaching a 20-mer asODN to a complementary sense strand through a heterobifunctional photocleavable linker. Cellular RNase H assays showed a greater than 10-fold increase in RNA degradation upon photoactivation of the asODN/sODN hairpin. Our lab has recently developed peptide nucleic acid (PNA) conjugates whose antisense function is transiently blocked by a complementary 2'-OMe RNA strand. By this approach, we have succeeded in regulating the expression of two different genes in the developing zebrafish embryo.