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Mutation of a Conserved Nuclear Export Sequence in Chikungunya Virus Capsid Protein Disrupts Host Cell Nuclear Import

Susan C Jacobs1, Adam Taylor2, Lara J Herrero3

  • 1The Roslin Institute, The University of Edinburgh, Midlothian EH25 9RG, UK. jacobs_susan@hotmail.com.

Viruses
|October 21, 2017
PubMed

Insights

Chikungunya virus (CHIKV) capsid protein moves to the nucleus, but unlike other alphaviruses, it doesn't shut down host cells. Its nuclear export is CRM1-dependent, and mutations block nuclear entry.

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • Chikungunya virus (CHIKV) causes widespread arthritic disease outbreaks.
  • CHIKV is an arthritogenic alphavirus within the Togaviridae family.
  • The CHIKV capsid protein can translocate into the host cell nucleus, but its role in arthritogenic alphaviruses is not fully understood.

Purpose of the Study:

  • To investigate the nuclear import and export mechanisms of the CHIKV capsid protein.
  • To characterize the function of a putative nuclear export sequence (NES) in the CHIKV capsid protein.
  • To compare the nuclear interactions of CHIKV capsid protein with those of encephalitic alphaviruses.

Main Methods:

  • Utilized CHIKV replicon systems to study capsid protein nuclear localization.
  • Investigated the role of a nuclear export sequence (NES) in the N-terminal region of the capsid protein.
  • Examined the involvement of the chromosomal maintenance 1 (CRM1) export adaptor protein in nuclear export.
  • Assessed the impact of NES mutations on host protein nuclear import.

Main Results:

  • CHIKV capsid protein possesses an NES in its N-terminal region, mediating nuclear export via CRM1.
  • A specific N-terminal region is crucial for the active nuclear targeting of CHIKV capsid protein.
  • Unlike encephalitic alphaviruses, CHIKV capsid protein does not inhibit host nuclear import.
  • Mutation of the NES in the CHIKV capsid protein (∆NES) blocked host protein access to the nucleus.

Conclusions:

  • CHIKV capsid protein undergoes CRM1-dependent nuclear export.
  • Nuclear targeting and export of CHIKV capsid protein are critical for its function.
  • While CHIKV capsid protein doesn't inhibit host nuclear import, its nuclear presence impacts nuclear transport.
  • Further research is needed to elucidate the complete interactions between CHIKV capsid protein and the host cell nucleus.
Keywords:
alphaviruscapsid proteinchikungunya virusnuclear export

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