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Veterinary research communications2026; 50(3); 239; doi: 10.1007/s11259-026-11187-3

Nucleolar proteins nucleolin and nucleophosmin 1 differentially relocalize during equid alphaherpesvirus 1 (EHV1) infection.

Abstract: We investigated equine nucleolar proteins nucleophosmin 1 (NPM1) and nucleolin (NCL) during EHV1 infection to develop understanding of EHV1-nucleolar interactions. Equine NPM1 primarily localized throughout nucleoli whereas NCL accumulated in a peri-nucleolar ring and localized throughout the nucleoplasm. EHV1 did not notably affect NPM1 or NCL protein levels but did alter their subnuclear localization. NPM1 accumulated in EHV1 replication compartments and remained nucleolus-associated until very late infection stages, characterized by a kidney bean-shaped nucleus and round cell morphology. NCL remained distributed throughout the nucleus although it dispersed from nucleoli. EHV1 thus differentially alters NPM1 and NCL subnuclear and nucleolar localization.
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Publication Date: 2026-03-30 PubMed ID: 41910830PubMed Central: PMC13035644DOI: 10.1007/s11259-026-11187-3Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This research investigates how two equine nucleolar proteins, nucleophosmin 1 (NPM1) and nucleolin (NCL), relocate within the cell nucleus during infection by equid alphaherpesvirus 1 (EHV1).
  • It identifies distinct changes in their subnuclear positioning without significant changes in protein levels, suggesting differential interactions between EHV1 and these nucleolar proteins.

Background and Purpose

  • Nucleoli are nuclear substructures involved primarily in ribosome production but also play roles in cell stress responses and viral infections.
  • Nucleolin (NCL) and nucleophosmin 1 (NPM1) are key nucleolar proteins with diverse functions including nucleic acid binding, ribosome assembly, and regulation of cell proliferation.
  • Equid alphaherpesvirus 1 (EHV1) is a virus affecting horses, and understanding how it interacts with host nucleolar proteins can shed light on viral replication mechanisms and host-pathogen interactions.
  • The study aims to delineate the localization changes of NPM1 and NCL during EHV1 infection in equine cells to understand the functional implications of these changes.

Methods

  • Equine cells were infected with EHV1 and analyzed at different stages of infection.
  • Immunolabeling and microscopy techniques were used to determine the localization patterns of NPM1 and NCL within the nucleus and nucleolus.
  • Protein levels of NPM1 and NCL were monitored to check whether EHV1 infection affected their expression.
  • Changes in nuclear and cellular morphology were also assessed as indicators of late-stage infection.

Key Findings

  • Under normal conditions, NPM1 is primarily distributed throughout the nucleoli, while NCL shows a peri-nucleolar ring pattern and is also found throughout the nucleoplasm.
  • EHV1 infection does not significantly change the overall protein levels of either NPM1 or NCL.
  • However, EHV1 alters their spatial distribution within the nucleus:
    • NPM1 accumulates within viral replication compartments and remains associated with the nucleolus up until very late stages of infection.
    • At late infection, nuclei take on a characteristic “kidney bean” shape, and infected cells exhibit round morphology.
    • NCL disperses from the nucleoli and remains spread throughout the nucleus without concentrating in viral replication centers.

Implications

  • The differential relocalization of NPM1 and NCL suggests distinct roles during EHV1 infection.
  • NPM1’s accumulation in viral replication compartments might indicate a functional involvement in viral DNA replication or assembly processes.
  • NCL dispersal could reflect disruption of nucleolar integrity or redistribution of nucleic acid-binding proteins to facilitate viral replication or impact host cell functions.
  • Overall, these findings contribute to understanding how EHV1 manipulates host nuclear architecture and nucleolar proteins to support its replication cycle.
  • This knowledge may guide future research on antiviral targets related to nucleolar protein interactions.

Conclusion

  • The study reveals that EHV1 infection induces specific rearrangements in nucleolar protein localization without altering their expression.
  • Nucleophosmin 1 and nucleolin have distinct subnuclear responses to viral infection, reflecting their potentially different functions or interactions with viral components.
  • These observations provide a foundation for further studies on the role of nucleolar proteins in herpesvirus infection and pathogenesis in equine hosts.

Cite This Article

APA
Kellerer L, Conn KL. (2026). Nucleolar proteins nucleolin and nucleophosmin 1 differentially relocalize during equid alphaherpesvirus 1 (EHV1) infection. Vet Res Commun, 50(3), 239. https://doi.org/10.1007/s11259-026-11187-3

Publication

Veterinary research communications
ISSN: 1573-7446
NlmUniqueID: 8100520
Country: Switzerland
Language: English
Volume: 50
Issue: 3
PII: 239

Researcher Affiliations

Kellerer, Laura
  • Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada.
Conn, Kristen L
  • Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada. kristen.conn@usask.ca.

MeSH Terms

  • Animals
  • Nucleolin
  • Nucleophosmin
  • Nuclear Proteins / metabolism
  • Nuclear Proteins / genetics
  • RNA-Binding Proteins / metabolism
  • RNA-Binding Proteins / genetics
  • Phosphoproteins / metabolism
  • Phosphoproteins / genetics
  • Horses
  • Horse Diseases / virology
  • Horse Diseases / metabolism
  • Herpesvirus 1, Equid / physiology
  • Herpesviridae Infections / veterinary
  • Herpesviridae Infections / virology
  • Herpesviridae Infections / metabolism
  • Cell Nucleolus / metabolism
  • Cell Nucleolus / virology

Grant Funding

  • Startup Funds / University of Saskatchewan

Conflict of Interest Statement

Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare that they have no competing interests.

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