Intracellular Light‐Activation of Riboswitch Activity

Abstract

By combining a riboswitch with a cell-permeable photocaged small molecule ligand, an optochemical gene control element was constructed, enabling spatial and temporal control of gene expression in bacterial cells. Because of the simplicity of this strategy, coupled with the ability to create synthetic riboswitches with tailored ligand specificities and output in a variety of microorganisms, plants, and fungi, this approach may afford a general strategy to photo-control gene expression in vivo. The ability to activate riboswitches using light enables the interrogation and manipulation of a wide range of biological processes with high precision, and will have broad utility in regulation of artificial genetic circuits.

Photocaged Arabinose: A Novel Optogenetic Switch for Rapid and Gradual Control of Microbial Gene Expression

“…[7] However,f ull releaseo fb ioactive IPTG is at wo-step process that involves hydrolytic cleavageo f the photosensitive protection group nitropiperonal by acellular esterase, because light exposure only yields accumulation of nonfunctional ester intermediates. [8] In this work, we developed, fort he first time, one-step photocleavablei nducers to drive arabinose-inducible bacterial gene expression upon short light exposure, without the requirementf or additional factorss uch as specific cellular enzymeso rt arget gene sequence ( Figure 1). In addition, as ophisticated riboswitch for activation of protein production was developed with caged theophylline, the functionality of which was strictly dependento nt arget gene region,though.…”

“…ChemBioChem 2016, 17,296 -299 www.chembiochem.org contrastt os imilarly sophisticated setups using photocaged theophylline [8] or IPTG, [7] this optogenetic toolp erforms independently of the target DNA downstream of the promoter (unlikec aged theophylline) or secondary cellular reactions (unlikec aged IPTG). A) Synthesisof4a and 4b:a)Ag 2 CO 3 (0.6 equiv), AgOTf (0.6 equiv), CH 2 Cl 2 ,R T; b) NaOMe (0.23 m in MeOH), Dowex 650C.…”

“…In addition, as ophisticated riboswitch for activation of protein production was developed with caged theophylline, the functionality of which was strictly dependento nt arget gene region,though. [8] In this work, we developed, fort he first time, one-step photocleavablei nducers to drive arabinose-inducible bacterial gene expression upon short light exposure, without the requirementf or additional factorss uch as specific cellular enzymeso rt arget gene sequence ( Figure 1). Twop hotocaged arabinosec ompounds were synthesized in at hree-step reac- Figure 1.…”

The concept of photochemical enzyme models – State of the art

“…Such optochemical tools can also be successfully employed for indirectly influencing more complex intracellular processes. For example gene expression controlled by riboswitches [180] can be manipulated using light as an external trigger [181] and sequential gene silencing becomes possible by introducing caged oligonucleotides [182] which has possible implications for the development of future therapeutic agents such as antisense drugs [183]. In addition, new techniques for bio-orthogonal ligation based on the photocleavage of protecting groups are now available to carry out selective and spatiallly resolved labelling of biomolecules in their native setting even within living organisms [184].…”

An open-hardware platform for optogenetics and photobiology

“…For example, light-switchable promoter systems have been engineered in E. coli 456789, cyanobacteria10, yeast1112, mammalian cells13141516171819202122, fruit flies23, zebrafish1924 and plants25. Translation2627, proteolysis28, membrane recruitment1129, signaling132930313233343536, ER-to-cytoplasm37 and nuclear38394041 translocation, and genome editing114243 have also been placed under optogenetic control.…”