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Updated: Jun 26, 2025
Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells
Published on: June 3, 2012
Identifying cellular RNA-binding proteins during infection uncovers a role for MKRN2 in influenza mRNA trafficking
Stefano Bonazza1, Hannah Leigh Coutts1, Swathi Sukumar1
1Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, United Kingdom.
Abstract:
Utilisation of RNA-binding proteins (RBPs) is an important aspect of post-transcriptional regulation of viral RNA. Viruses such as influenza A viruses (IAV) interact with RBPs to regulate processes including splicing, nuclear export and trafficking, while also encoding RBPs within their genomes, such as NP and NS1. But with almost 1000 RBPs encoded within the human genome it is still unclear what role, if any, many of these proteins play during viral replication. Using the RNA interactome capture (RIC) technique, we isolated RBPs from IAV infected cells to unravel the RBPome of mRNAs from IAV infected human cells. This led to the identification of one particular RBP, MKRN2, that associates with and positively regulates IAV mRNA. Through further validation, we determined that MKRN2 is involved in the nuclear-cytoplasmic trafficking of IAV mRNA potentially through an association with the RNA export mediator GLE1. In the absence of MKRN2, IAV mRNAs accumulate in the nucleus of infected cells, which may lead to their degradation by the nuclear RNA exosome complex. MKRN2, therefore, appears to be required for the efficient nuclear export of IAV mRNAs in human cells.
Insights
Researchers discovered that the RNA-binding protein MKRN2 is crucial for influenza A virus (IAV) replication. MKRN2 facilitates the export of viral messenger RNA (mRNA) from the nucleus to the cytoplasm, aiding virus survival.
Area of Science:
- Virology
- Molecular Biology
- Post-transcriptional Regulation
Background:
- RNA-binding proteins (RBPs) are key regulators of viral RNA post-transcriptional processes.
- Influenza A viruses (IAV) utilize host RBPs and encode their own (e.g., NP, NS1) for replication.
- The roles of many of the nearly 1000 human RBPs in viral replication remain largely unknown.
Purpose of the Study:
- To identify host RBPs that interact with IAV mRNA.
- To elucidate the function of identified RBPs in the IAV life cycle.
- To understand the mechanism of RBP-mediated regulation of viral RNA.
Main Methods:
- RNA interactome capture (RIC) was employed to isolate RBPs bound to IAV mRNA in infected human cells.
- MKRN2's association with IAV mRNA was confirmed through validation experiments.
- The impact of MKRN2 on IAV mRNA nuclear export and its potential interaction with GLE1 were investigated.
Main Results:
- MKRN2 was identified as a host RBP that binds to and positively regulates IAV mRNA.
- MKRN2 facilitates the nuclear-cytoplasmic trafficking of IAV mRNA, potentially via interaction with GLE1.
- Depletion of MKRN2 leads to nuclear accumulation of IAV mRNA, suggesting impaired export and potential degradation.
Conclusions:
- MKRN2 is essential for the efficient nuclear export of IAV mRNAs in human cells.
- MKRN2 plays a critical role in supporting IAV replication by promoting viral mRNA transport.
- Targeting MKRN2 could be a potential antiviral strategy against influenza A virus.
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