Related Experiment Video

Updated: Jun 13, 2026

Electrophoretic Analysis of Replication Through Structure-Prone DNA Repeats Within the SV40-Based Human Episome
05:22

Electrophoretic Analysis of Replication Through Structure-Prone DNA Repeats Within the SV40-Based Human Episome

Published on: September 13, 2024

SV40 exploits the Nesprin-2-SUN1-KPNA4 axis for stepwise targeting and entry into the host nucleus to promote

Luke Gohmann1,2, Billy Tsai1,2

  • 1Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America.

Plos Pathogens
|June 11, 2026
PubMed

Insights

Simian virus 40 (SV40) uses Nesprin-2 and SUN1 proteins to reach the nuclear membrane. It then binds KPNA4 to enter the nucleus, revealing a novel DNA virus infection pathway.

Area of Science:

  • Cell Biology
  • Virology
  • Molecular Biology

Background:

  • DNA viruses, including polyomaviruses (PyVs), infect host cells by entering the nucleus.
  • The precise mechanisms of nuclear entry for PyVs, such as Simian virus 40 (SV40), remain incompletely understood.
  • SV40 is known to interact with the outer nuclear membrane protein Nesprin-2 and utilize the nuclear pore complex (NPC) for entry.

Purpose of the Study:

  • To identify host factors that cooperate with Nesprin-2 for SV40 nuclear targeting.
  • To elucidate the mechanism of SV40 nuclear entry dependent on the nuclear pore complex (NPC).
  • To understand how SV40 utilizes the Nesprin-2-SUN1-KPNA4 axis for nuclear translocation.

Main Methods:

  • Co-immunoprecipitation assays to identify protein interactions.
  • Confocal microscopy to visualize SV40 localization and interactions with nuclear envelope proteins.
  • Functional assays to assess the role of SUN1 and KPNA4 in SV40 nuclear import.

Main Results:

  • SUN1, an inner nuclear membrane protein, works with Nesprin-2 to target cytosolic SV40 to the nuclear membrane.
  • The SUN domain of SUN1 is critical for recruiting SV40 to the nuclear membrane via Nesprin-2.
  • SV40 binds to KPNA4, an importin receptor associated with the NPC, facilitating its translocation into the nucleus.

Conclusions:

  • SV40 exploits a pathway involving Nesprin-2, SUN1, and KPNA4 for efficient nuclear entry.
  • This study reveals a stepwise mechanism for DNA virus nuclear targeting and import.
  • Understanding this pathway provides insights into viral infection strategies and potential therapeutic targets.

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