Related Experiment Video
Updated: May 14, 2026
06:44
Confocal Imaging of Double-Stranded RNA and Pattern Recognition Receptors in Negative-Sense RNA Virus Infection
Published on: January 26, 2019
Dicer-2 processes diverse viral RNA species
Leah R Sabin1, Qi Zheng, Pramod Thekkat
1Department of Microbiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
Plos One
|February 21, 2013
Summary
RNA interference (RNAi) pathways use Dicer-2 to generate virus-specific small interfering RNAs (siRNAs) from viral RNA. This study identifies novel viral RNA targets and shows viral suppressors can alter RNAi responses.
Area of Science:
- Molecular Biology
- Virology
- Immunology
Background:
- RNA silencing pathways, including RNA interference (RNAi), are crucial for gene regulation and host defense against viruses.
- RNA interference relies on Dicer enzymes to process double-stranded RNA (dsRNA) into small interfering RNAs (siRNAs) that guide the RNA-induced silencing complex (RISC) to target RNAs.
- The range of viral RNA substrates recognized and processed by Dicer proteins, particularly Dicer-2 in insects, remains incompletely understood.
Purpose of the Study:
- To comprehensively identify and characterize the virus-derived small interfering RNAs (siRNAs) generated during the Drosophila antiviral RNAi response.
- To elucidate the specific viral RNA structures and sequences targeted by Dicer-2.
- To investigate the impact of viral RNAi suppressors on Dicer-2 substrate recognition.
Main Methods:
- High-throughput sequencing of virus-derived siRNAs from Drosophila infected with four distinct viruses.
- Bioinformatic analysis to identify siRNA origins and target RNA structures within viral genomes.
- Comparative analysis of siRNA production in the presence and absence of viral RNAi suppressors.
Main Results:
- Each of the four viruses examined was uniquely targeted by the RNAi pathway, with Dicer-2 processing dsRNA replication intermediates and intramolecular RNA stem loops.
- A specific RNA hairpin in Rift Valley Fever virus and repetitive sequences in Vaccinia virus termini were identified as abundant siRNA sources in insect cells.
- The study provides evidence that viral RNA species targeted by Dicer-2 can be modulated by viral RNAi suppressor proteins.
Conclusions:
- Dicer-2 targets diverse viral RNA structures, including replication intermediates and hairpin RNAs, during antiviral defense.
- Novel viral genomic features susceptible to RNAi have been identified, offering insights into viral replication and immune evasion.
- Understanding these interactions is key to deciphering antiviral RNAi mechanisms and viral pathogenesis.
Related Concept Videos
01:29Viruses with RNA Genomes
RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...
01:26Size and Structure of Viral Genomes
Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
02:30siRNA - Small Interfering RNAs
Small interfering RNAs, or siRNAs, are short regulatory RNA molecules that can silence genes post-transcriptionally, as well as the transcriptional level in some cases. siRNAs are important for protecting cells against viral infections and silencing transposable genetic elements.
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
In the cytoplasm, siRNA is processed from a double-stranded RNA, which comes from either endogenous DNA transcription or exogenous sources like a virus. This double-stranded RNA is then cleaved by the ATP-dependent...
01:10Retrovirus Life Cycles
Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...
01:23RNA Interference
RNA interference (RNAi) is a process in which a small non-coding RNA molecule blocks the post-transcriptional expression of a gene by binding to its messenger RNA (mRNA) and preventing the protein from being translated.
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
01:23RNA Interference
RNA interference (RNAi) is a process in which a small non-coding RNA molecule blocks the post-transcriptional expression of a gene by binding to its messenger RNA (mRNA) and preventing the protein from being translated.
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...