Engineering self-contained DNA circuit for proximity recognition and localized signal amplification of target biomolecules

Abstract

Biomolecular interactions have important cellular implications, however, a simple method for the sensing of such proximal events is lacking in the current molecular toolbox. We designed a dynamic DNA circuit capable of recognizing targets in close proximity to initiate a pre-programmed signal transduction process resulting in localized signal amplification. The entire circuitwas engineered to be self-contained, i.e. it can self-assemble onto individual target molecules autonomously and form localized signal withminimal cross-talk. α-thrombin was used as a model protein to evaluate the performance of the individual modules and the overall circuit for proximity interaction under physiologically relevant buffer condition. The circuit achieved good selectivity in presence of nonspecific protein and interfering serum matrix and successfully detected for physiologically relevant α-thrombin concentration (50 nM-5 μM) in a singlemixing step without any further washing. The formation of localized signal at the interaction site can be enhanced kinetically through the control of temperature and probe concentration. This work provides a basic general framework from which other circuit modules can be adapted for the sensing of other biomolecular or cellular interaction of interest. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.