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Temporal Analysis of the Nuclear-to-cytoplasmic Translocation of a Herpes Simplex Virus 1 Protein by Immunofluorescent Confocal Microscopy
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Temporal Analysis of the Nuclear-to-cytoplasmic Translocation of a Herpes Simplex Virus 1 Protein by Immunofluorescent Confocal Microscopy

Published on: November 4, 2018

C-terminal region of herpes simplex virus ICP8 protein needed for intranuclear localization

Travis J Taylor1, David M Knipe

  • 1Department of Microbiology and Molecular, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.

Virology
|May 22, 2003
PubMed

Insights

Herpes simplex virus ICP8 protein localization to nuclear prereplicative sites is crucial for viral replication. A specific C-terminal alpha-helix in ICP8 mediates this localization, potentially by interacting with other viral or cellular factors.

Area of Science:

  • Molecular Virology
  • Cellular Biology
  • Protein Localization

Background:

  • Herpes simplex virus (HSV) DNA replication involves the viral single-stranded DNA-binding protein, ICP8.
  • ICP8 initially localizes to nuclear prereplicative sites, which mature into replication compartments as replication progresses.
  • Mechanisms governing ICP8 redistribution and its role in nuclear protein localization are not fully understood.

Purpose of the Study:

  • To identify the specific region and residues within HSV ICP8 responsible for its localization to prereplicative sites.
  • To investigate the role of a predicted C-terminal alpha-helix in ICP8 nuclear targeting and function.
  • To elucidate the mechanism by which ICP8 is retained at specific intranuclear locations.

Main Methods:

  • Site-specific and random mutagenesis of the ICP8 gene, focusing on a predicted C-terminal alpha-helical region.
  • Analysis of ICP8 mutant protein localization within infected cell nuclei using microscopy.
  • Assessment of dominant-negative inhibitory effects of mutant ICP8 proteins on viral replication.
  • Investigation of ICP8 interaction with the U(L)9 origin-binding protein.

Main Results:

  • Proline substitutions within the predicted C-terminal alpha-helix abolished ICP8 localization to prereplicative sites and conferred dominant-negative activity.
  • Mutations altering charged residues in the alpha-helix had minimal impact on ICP8 nuclear localization.
  • The identified alpha-helix was not required for ICP8 interaction with the U(L)9 protein.

Conclusions:

  • A specific C-terminal alpha-helix in HSV ICP8 is essential for its proper localization to nuclear prereplicative sites.
  • This helix likely mediates ICP8 nuclear targeting by interacting with viral or cellular factors.
  • Proper ICP8 localization is critical for its function in HSV DNA replication.

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