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Alpha/beta interferons fail to induce antiviral activity from within the nucleus
I Riviere1, J de Maeyer-Guignard
1Centre National de la Recherche Scientifique, URA 1343, Institut Curie, Université de Paris-Sud, Orsay, France.
Journal of Virology
|May 1, 1990
Summary
Directly injecting alpha/beta interferons (IFN-alpha/beta) into mouse cell nuclei did not trigger an antiviral state. These findings challenge the role of nuclear binding sites and support cell surface receptor signaling for IFN-alpha/beta activity.
Area of Science:
- Immunology
- Cell Biology
- Virology
Background:
- Alpha/beta interferons (IFN-alpha/beta) are crucial for antiviral defense.
- The precise mechanism of IFN-alpha/beta signaling, including potential nuclear roles, is under investigation.
- Previous studies suggested possible nuclear binding sites for interferons.
Purpose of the Study:
- To investigate the functional significance of intranuclear alpha/beta interferons (IFN-alpha/beta).
- To determine if direct nuclear delivery of IFN-alpha/beta can induce an antiviral state.
- To evaluate the necessity of nuclear localization for interferon-mediated antiviral activity.
Main Methods:
- Murine alpha/beta interferons (IFN-alpha/beta) were microinjected into the nuclei of mouse L cells.
- Injected cells were subsequently challenged with vesicular stomatitis virus or Semliki Forest virus.
- The presence of cytopathic effects was assessed in individual cells at 3, 6, and 24 hours post-injection.
Main Results:
- Intranuclear delivery of IFN-alpha/beta did not induce an antiviral state in any of the tested cells.
- Over 1,000 cells were analyzed across nine experiments, yielding consistent negative results.
- These findings contradict the hypothesis that high-affinity nuclear binding sites are physiologically important for native IFN-alpha/beta.
Conclusions:
- The results strongly suggest that intranuclear IFN-alpha/beta is not sufficient to initiate the antiviral response.
- This study supports the model where IFN-alpha/beta binding to cell surface receptors triggers transmembrane signaling without requiring internalization.
- The findings underscore the importance of the plasma membrane as the primary site for initiating interferon-induced antiviral mechanisms.