Characterization of an Autographa californica multiple nucleopolyhedrovirus dual mutant: ORF82 is required for budded virus production, and a point mutation in LEF-8 alters late and abolishes very late transcription.
A temperature-sensitive (ts) Autographa californica multiple nucleopolyhedrovirus dual mutant, ts42, was generated that displayed tiny-plaque and polyhedral inclusion body (PIB)-defective phenotypes at 33 °C. The mutation responsible for the tiny-plaque phenotype was mapped to orf82, which was characterized as a late gene. Its product was not studied. The mutation responsible for the PIB-defective phenotype was mapped to a highly conserved region of lef-8, which encodes the largest subunit of the viral RNA polymerase. These mutations did not cause a global defect in viral DNA replication or a defect in the shutoff of host protein synthesis. However, the mutation in orf82 caused a dramatic defect in the production of progeny budded virus (BV) but did not decrease the infectivity of those BVs that were released. Hence, ORF82 is required for BV production. The mutation in lef-8 affected a conserved residue that is part of a highly conserved region of LEF-8. This mutation abolished very late transcription whilst altering the transcript size and level of transcription of two late genes.
Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA.
David
D
Gauthier
Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA.
Kannan
K
Thirunavukkarasu
Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA.
Brian L
BL
Faris
Department of Biology, Baker University, Baldwin City, KS 66006, USA.
Darcy L
DL
Russell
Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA.
Robert F
RF
Weaver
D004252:DNA Mutational Analysis; D007181:Inclusion Bodies, Viral; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D017354:Point Mutation; D014158:Transcription, Genetic; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D057074:Virus Release
D050505:Mutant Proteins; D014764:Viral Proteins