Orthogonal Activation of RNA‐Cleaving DNAzymes in Live Cells by Reactive Oxygen Species

Abstract

RNA-cleaving DNAzymes are useful tools for intracellular metal-ion sensing and gene regulation. Incorporating stimuli-responsive modifications into these DNAzymes enables their activities to be spatiotemporally and chemically controlled for more precise applications.Despite the successful development of many caged DNAzymes for light-induced activation, DNAzymes that can be intracellularly activated by chemical inputs of biological importance,s uch as reactive oxygen species (ROS), are still scarce.R OS like hydrogen peroxide( H 2 O 2 )a nd hypochlorite (HClO) are critical mediators of oxidative stress-related cell signaling and dysregulation including activation of immune system as well as progression of diseases and aging.H erein, we report ROS-activable DNAzymes by introducing phenylboronate and phosphorothioate modifications to the Zn 2+ -dependent 8-17 DNAzyme. These ROS-activable DNAzymes were orthogonally activated by H 2 O 2 and HClO inside live human and mouse cells.

Photocontrol of CRISPR/Cas9 function by site-specific chemical modification of guide RNA

“…Our design of site-specic photoactivable gRNA presented a new pathway for modication of RNA based on the RNA-protein interaction rather than RNA itself. More than optical control, these specic sites could be also modied with other stimuliresponsive groups, 54,56,57 which would potentially further enrich the toolbox for conditional control of CRISPR-Cas9 function in the future.…”

An Enzyme‐Activatable Engineered DNAzyme Sensor for Cell‐Selective Imaging of Metal Ions

“…For example, irregular concentrations of metal ions are implicated in a variety of cancers [3, 4] . In order to elucidate their role in diverse pathological processes, DNAzyme, a class of functional DNA that possess catalytic activity, [5, 6] have been widely investigated for development of metal‐ion sensors [7–26] . Compared with small molecular probe, DNAzymes obtained by the in vitro selection have the merits of easy synthesis, high programmability and sensitivity for almost any metal ion [7, 9, 10] .…”

Enzyme‐Mediated Endogenous and Bioorthogonal Control of a DNAzyme Fluorescent Sensor for Imaging Metal Ions in Living Cells

“…However, unlike exogenous controls, endogenous controls must be biologically orthogonal so that the control will not trigger or interfere with other biological events. Toward this goal, DNAzymes activated by reactive oxygen species (ROS) were recently reported by modification of either phenylboronate or phosphorothioate to the DNAzymes, in which either H 2 O 2 or HClO, respectively, are used as triggers to activate the DNAzymes for intracellular metal‐ion sensing . Even though this strategy can achieve activation in the live cell environment, the introduction of exogenous ROS species inevitably induces damage in living cells.…”