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Updated: Oct 12, 2025
Affinity Purification of Influenza Virus Ribonucleoprotein Complexes from the Chromatin of Infected Cells
Published on: June 3, 2012
Human sorting nexin 2 protein interacts with Influenza A virus PA protein and has a negative regulatory effect on the
Tuğba Koçmar1, Elif Çağlayan2, Erkan Rayaman3
1Institute of Health Sciences, Marmara University, Istanbul, Turkey.
Background:
Replication of the influenza A viruses occurs in the cells through the viral RdRP consisting of PB1, PB2, and PA. Several cellular proteins are involved in these processes. This study aims to reveal the interaction between human SNX2 protein and the PA protein and the effects of the SNX2 on the virus replication.
Results:
To identify potential host interacting proteins to the PA, yeast two-hybrid assay was carried out with HEK293 cell cDNA library and the PA as a bait. We focused on SNX2 protein, which interacts with the PA in the yeast cells. By using the co-immunoprecipitation assays, it has been demonstrated that the amino-terminal part of the PA was important for binding to the SNX2. Immunolocalization of the proteins in HeLa cells supported this interaction. Knockdown of the SNX2 with siRNA in the cells resulted in a significant increase in both viral transcripts and virus growth. However, the increase of SNX2 in transfected cells didn't cause a significant change in the viral RdRP activity in minireplicon assay. This may suggest that the negative effect of SNX2 on the virus replication could be saturated with its authentic intra-cellular amount.
Conclusions:
This study revealed that the SNX2 and PA protein interact with each other in both yeast and HEK293 cells, and the SNX2 has a negative regulatory function on the virus replication. However, more knowledge is required to elucidate the action mechanism of the SNX2 on the influenza A virus replication at the molecular level.
Insights
Human SNX2 protein interacts with influenza A virus PA protein, negatively regulating viral replication. Increased SNX2 levels enhance viral transcripts and growth, suggesting a key role in host-pathogen interactions.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Influenza A virus replication relies on the viral RNA-dependent RNA polymerase (RdRP) complex (PB1, PB2, PA) and host factors.
- Understanding host-pathogen interactions is crucial for developing antiviral strategies.
Purpose of the Study:
- To investigate the interaction between human SNX2 protein and influenza A virus PA protein.
- To determine the effect of SNX2 on influenza A virus replication.
Main Methods:
- Yeast two-hybrid assay to identify interacting proteins.
- Co-immunoprecipitation and immunolocalization to confirm and characterize the interaction.
- siRNA-mediated knockdown and minireplicon assays to assess SNX2's effect on viral replication.
Main Results:
- SNX2 was identified as a binding partner of the PA protein.
- The N-terminal region of PA is crucial for SNX2 binding.
- SNX2 knockdown significantly increased viral RNA and virus production.
- Overexpression of SNX2 did not significantly alter RdRP activity in minireplicon assays, suggesting saturation.
Conclusions:
- SNX2 interacts with the influenza A virus PA protein.
- SNX2 negatively regulates influenza A virus replication.
- Further research is needed to elucidate the molecular mechanisms underlying SNX2's antiviral activity.
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