Light‐Activated RNA Interference

Abstract

The process of RNA interference can be controlled with light. On the following pages, S. H. Friedman and co-workers demonstrate that siRNAs modified with photolabile groups have reduced ability to effect RNA interference until irradiation deprotects them and releases fully active siRNA.

Light-Activatable Nucleic Acids 'Caged' at the Nucleobases

“…[10] (n = 1, R = adenine) and Chaulk and MacMillan [11] (n = 0, R = cytosine) introduced RNA derivatives with caging groups at the 2'-OH position. (b) Haselton, Monroe and coworkers, [13,14] Okamoto and coworkers [15] and the Friedman group [16] modified whole nucleic acids under benzylating conditions 'statistically'. [17] As demonstrated in the graph the system showed a clean ON/OFF behavior.…”

“…Thus for example Haselton, Monroe and coworkers [13,14] or the Okamoto group [15] modified plasmid DNA or mRNA and Friedman modified siRNAs. [16] In each case it was difficult to obtain a good ON/ OFF-behavior which is most likely due to the fact that the modified positions in the nucleic acids were not well defined. Therefore we decided to make new derivatives of DNA and RNA which should bear photolabile groups at the nucleobases in such a way that the formation of Watson-Crick interactions becomes temporarily impossible.…”

Photo-dependent protein biosynthesis using a caged aminoacyl-tRNA

“…Photo-regulation of translation has been achieved using caged compounds, 9 such as caged mRNA 10 and a photoresponsive 5 0 -cap. 11 Photo-regulation of translation has also been achieved by siRNA-mediated methods, such as caged siRNA technologies [12][13][14] and CLIP-RNAi. [15][16][17][18] All these methods control the activity or concentration of the target mRNA.…”

Nucleic Acid Binders Activated by Light of Selectable Wavelength

“…[8] Friedman and co-workers used a similar strategy for caging siRNAs. [9] In practically all reported examples uncaging is done with UV light. [2] Light of this type is strongly absorbed by cellular components and is damaging to the cells.…”