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Updated: Jun 8, 2026
09:05
MicroRNA-based Regulation of Picornavirus Tropism
Published on: February 6, 2017
Noncanonical cytoplasmic processing of viral microRNAs
Jillian S Shapiro1, Andrew Varble, Alissa M Pham
1Microbiology Graduate School Training Program, Mount Sinai School of Medicine, New York, New York 10029, USA.
RNA (New York, N.Y.)
|September 16, 2010
Summary
Vertebrates may use RNA interference (RNAi) against viruses via viral mirtrons (virtrons). These small RNAs, processed independently of known pathways, show sequence-specific antiviral activity, suggesting a novel defense mechanism.
Area of Science:
- Virology
- Molecular Biology
- Immunology
Background:
- RNA interference (RNAi) is a known antiviral mechanism in plants and invertebrates.
- Vertebrate antiviral defenses primarily rely on interferons (IFNs), with small RNAs typically regulating host transcripts via microRNAs (miRNAs).
Purpose of the Study:
- To investigate the potential for RNAi-like antiviral activity in vertebrates using modified viruses.
- To characterize the processing and function of viral small RNAs in a vertebrate cellular context.
Main Methods:
- Incorporation of a primary miRNA into a cytoplasmic virus.
- Analysis of viral small RNA processing using Dicer and DGCR8 dependency assays.
- Assessment of RNAi-like activity and antiviral effects on viral replication.
Main Results:
- A primary miRNA integrated into a virus formed a mature, Dicer-dependent, DGCR8-independent miRNA (virtron).
- Virtrons exhibited RNAi-like activity, inducing post-transcriptional gene silencing and sequence-specific, IFN-independent interference with viral replication.
- Virtron processing mirrored endogenous miRNA maturation but conferred antiviral defense.
Conclusions:
- Vertebrates may possess a noncanonical antiviral pathway utilizing small RNAs derived from cytoplasmic viral elements.
- This pathway involves Dicer-dependent processing of viral hairpins, independent of the microprocessor complex and IFN signaling.
- Virtrons represent a novel class of small RNAs with potential roles in cellular antiviral defense.
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