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Published on: February 22, 2018
In vivo induction of apoptosis correlating with reduced infectivity during baculovirus infection
Thomas E Clarke1, Rollie J Clem
1Molecular, Cellular, and Developmental Biology Program, Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA.
Abstract:
Spodoptera frugiperda caterpillars were infected with a mutant of Autographa californica M nucleopolyhedrovirus lacking the antiapoptotic p35 gene. Viral infectivity, replication, and spread were substantially reduced compared to that of a control revertant virus. Terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling confirmed that apoptosis occurred in mutant-infected caterpillars, thus directly correlating reduced infectivity and in vivo induction of apoptosis.
Insights
The anti-apoptotic p35 gene is crucial for Autographa californica M nucleopolyhedrovirus (AcMNPV) infection in Spodoptera frugiperda caterpillars. Removing this gene significantly reduces viral replication and spread, inducing apoptosis.
Area of Science:
- Virology
- Insect Pathology
- Molecular Biology
Background:
- Autographa californica M nucleopolyhedrovirus (AcMNPV) is a baculovirus that infects lepidopteran pests.
- The p35 gene in AcMNPV encodes a protein that inhibits apoptosis, a key host defense mechanism.
- Understanding the role of p35 is critical for developing effective viral biocontrol agents.
Purpose of the Study:
- To investigate the role of the anti-apoptotic p35 gene of AcMNPV in viral infectivity and replication in Spodoptera frugiperda.
- To determine if the absence of the p35 gene directly correlates with the induction of apoptosis in infected insects.
Main Methods:
- Infection of Spodoptera frugiperda caterpillars with a mutant AcMNPV lacking the p35 gene.
- Comparison of viral infectivity, replication, and spread with a control revertant virus.
- Detection of apoptosis using Terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay.
Main Results:
- Viral infectivity, replication, and spread were significantly reduced in caterpillars infected with the p35-deficient mutant compared to the control.
- TUNEL assay confirmed the occurrence of apoptosis in caterpillars infected with the mutant virus.
- A direct correlation was established between the reduced viral infectivity and the in vivo induction of apoptosis.
Conclusions:
- The p35 gene is essential for efficient AcMNPV infection and replication in Spodoptera frugiperda.
- The absence of p35 leads to the induction of apoptosis, which impairs viral propagation.
- These findings highlight the importance of viral apoptosis inhibitors in baculovirus pathogenesis and potential for biocontrol strategies.
