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Autographa californica multiple nucleopolyhedrovirus ac142, a core gene that is essential for BV production and ODV

Christina B McCarthy1, Xiaojiang Dai, Cam Donly

  • 1Pacific Agri-Food Research Centre, Agriculture and Agri-Food Canada, Box 5000, Summerland, British Columbia, Canada V0H 1Z0.

Virology
|November 30, 2007
PubMed

Insights

The Autographa californica multiple nucleopolyhedrovirus ac142 gene is essential for producing infectious budded virus (BV). Deleting this gene prevents nucleocapsid envelopment and occlusion, halting viral spread.

Area of Science:

  • Virology
  • Molecular Biology
  • Insect Pathology

Background:

  • Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a significant pathogen affecting insects.
  • The ac142 gene is a core baculovirus gene encoding a protein associated with occlusion-derived virus (ODV).

Purpose of the Study:

  • To elucidate the function of the AcMNPV ac142 gene in the viral life cycle.
  • To investigate the role of AC142 protein in virus assembly and infectivity.

Main Methods:

  • Generation of an ac142 deletion mutant virus (AcBAC(ac142KO-PH-GFP)) using the AcMNPV bacmid system.
  • Fluorescence and light microscopy for infection phenotype analysis.
  • Titration assays and Western blotting to assess viral production and protein expression.
  • Electron microscopy to examine virion structure and assembly.

Main Results:

  • AcBAC(ac142KO-PH-GFP) exhibited a single-cell infection phenotype, indicating impaired viral spread.
  • The deletion mutant was unable to produce infectious budded virus (BV), confirmed by titration and Western blot.
  • Viral DNA replication and occlusion body formation proceeded normally, suggesting late-stage assembly defects.
  • AC142 protein is a structural component of BV and ODV, localizing to nucleocapsids.
  • Electron microscopy revealed that ac142 is critical for nucleocapsid envelopment and ODV formation.

Conclusions:

  • The AC142 protein is indispensable for the formation of infectious ODV and BV.
  • AcMNPV ac142 plays a fundamental role in nucleocapsid envelopment and the subsequent occlusion process.
  • Understanding ac142 function is crucial for controlling baculovirus infections.

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