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

1

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)

(Py)A-cluster system for the detection and imaging of miRNAs in living cells through double-three-way junction formation

Herein, we describe an extended version of a fluorescence probe for detecting miRNAs through the novel application of a (Py)A-cluster system. By testing various (CG)(n) sequences in the middle of the oligonucleotide strand of the probe, we obtained an optimal sequence that formed a double-three-way-junction structure, with two (Py)A units positioned close together, in the presence of the target miRNA. This system readily detected the locations of target miRNAs in living cells and allowed visualization of structural changes through variations in the color of the fluorescence.11Nsciescopu