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The function of envelope protein P74 from Autographa californica multiple nucleopolyhedrovirus in primary infection

Wenke Zhou1, Lunguang Yao, Hua Xu

  • 1State Key Laboratory of Virology, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, PR China.

Virus Genes
|March 4, 2005
PubMed

Insights

The Autographa californica multiple nuclear polyhedrosis virus envelope protein P74 is crucial for oral infection of host larvae. P74 facilitates attachment and fusion in the insect midgut, essential for viral entry.

Area of Science:

  • Virology
  • Insect Pathology
  • Molecular Biology

Background:

  • Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) is a significant pathogen of lepidopteran pests.
  • The envelope protein P74 is implicated in baculovirus infection, but its precise role in oral infectivity is not fully understood.

Purpose of the Study:

  • To investigate the function of AcMNPV envelope protein P74 in the primary infection of host insects.
  • To determine the role of P74 in viral attachment and entry into host cells.

Main Methods:

  • Construction of a p74-inactivation recombinant baculovirus (rAc-gfp(Δ)p74).
  • Bioassays using Spodoptera exigua larvae, including per os feeding and injection.
  • Rescue experiments with wild-type virus or purified P74 protein.
  • ELISA and in vitro pull-down assays to analyze protein-membrane interactions.

Main Results:

  • P74-null occlusion bodies (OBs) were unable to infect S. exigua orally, but budded virus (BVs) retained infectivity via injection.
  • Oral infectivity was restored by co-infection with wild-type OBs or by adding purified P74 protein in a dose-dependent manner.
  • P74 protein specifically bound to midgut brush border membrane vesicles (BBMVs), with a 35 kDa BBMV protein involved in this interaction.

Conclusions:

  • The P74 protein is essential for the oral infectivity of occlusion-derived virus (ODV).
  • P74 plays a critical role in the attachment and fusion processes within the insect midgut.
  • Understanding P74's function can inform strategies for baculovirus-based pest control.

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