5′-Triphosphate-RNA-independent activation of RIG-I via RNA aptamer with enhanced antiviral activity

RIG-I is a cytosolic receptor for non-self RNA that mediates immune responses against viral infections through IFNα/β production. In an attempt to identify novel tools that modulate IFNα/β production, we used SELEX technology to screen RNA aptamers that specifically target RIG-I protein. Most of the selected RIG-I aptamers contained polyU motifs in the second half regions that played critical roles in the activation of RIG-I-mediated IFNβ production. Unlike other known ligands, RIG-I aptamer bound and activated RIG-I in a 5′-triphosphate-independent manner. The helicase and RD domain of RIG-I were used for aptamer binding, but intact RIG-I protein was required to exert aptamer-mediated signaling activation. Furthermore, replication of NDV, VSV and influenza virus in infected host cells was efficiently blocked by pre- or post-treatment with RIG-I aptamer. Based on these data, we propose that RIG-I aptamer has strong potential to be an antiviral agent that specifically boosts the RIG-I-dependent signaling cascade

Biosensing of miRNA and detection of its drug-interactions

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Fluorescent nucleic acid systems: design, construction, and biosensing

Fluorescent nucleic acid systems: design, construction, and biosensing1

Fluorescent nucleic acid systems: design, construction, and biosensing

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Published on Web 05/08/2004 A Highly Discriminating Quencher-Free Molecular Beacon for Probing DNA

Sequence-selective DNA detection is becoming increasingly important as a tool for monitoring many biological processes and for other biotechnological applications. One recent development is molecular beacons (MBs) that are highly selective in their recognition of oligonucleotides. 1 Traditional MBs are doubly end-labeled oligonucleotides that exist in solution as stable stem-loop structures in which the fluorescence of a reporter dye attached to the 5 ′ end is quenched through energy transfer to a proximate quencher attached to the 3 ′ end. In the presence of a complementary nucleic acid, the stem opens and this event is signaled by a loss of quenching and an increase in fluorescence. While MBs have been used efficiently as biosensors, their fluorophore/quencher systems are unnecessary for sequence-selective duplex formation and are utilized only as detection tools. Herein, we describe a new strategy for designing MBs possessing only a fluorophore (i.e., no quencher)