title: The sf32 unique gene of Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV) is a non-essential gene that could be involved in nucleocapsid organization in occlusion-derived virions.
abstract: A recombinant virus lacking the sf32 gene (Sf32null), unique to the Spodoptera frugiperda multiple nucleopolyhedrovirus (SfMNPV), was generated by homologous recombination from a bacmid comprising the complete viral genome (Sfbac). Transcriptional analysis revealed that sf32 is an early gene. Occlusion bodies (OBs) of Sf32null contained 62% more genomic DNA than viruses containing the sf32 gene, Sfbac and Sf32null-repair, although Sf32null DNA was three-fold less infective when injected in vivo. Sf32null OBs were 18% larger in diameter and contained 17% more nucleocapsids within ODVs than those of Sfbac. No significant differences were detected in OB pathogenicity (50% lethal concentration), speed-of-kill or budded virus production in vivo. In contrast, the production of OBs/larva was reduced by 39% in insects infected by Sf32null compared to those infected by Sfbac. The SF32 predicted protein sequence showed homology (25% identity, 44% similarity) to two adhesion proteins from Streptococcus pyogenes and a single N-mirystoylation site was predicted. We conclude that SF32 is a non-essential protein that could be involved in nucleocapsid organization during ODV assembly and occlusion, resulting in increased numbers of nucleocapsids within ODVs.
authors.affiliation: Instituto de Agrobiotecnología, CSIC-UPNA-Gobierno de Navarra, Mutilva Baja, Navarra, Spain.
authors.forename: Inés
authors.initials: I
authors.lastname: Beperet
authors.forename: Gloria
authors.initials: G
authors.lastname: Barrera
authors.forename: Oihane
authors.initials: O
authors.lastname: Simón
authors.forename: Trevor
authors.initials: T
authors.lastname: Williams
authors.forename: Miguel
authors.initials: M
authors.lastname: López-Ferber
authors.forename: Laila
authors.initials: L
authors.lastname: Gasmi
authors.forename: Salvador
authors.initials: S
authors.lastname: Herrero
authors.forename: Primitivo
authors.initials: P
authors.lastname: Caballero
mesh_terms: D000818:Animals; D004279:DNA, Viral / Q000235:genetics; D020043:Genes, Essential / Q000235:genetics; D016679:Genome, Viral / Q000235:genetics; D005838:Genotype; D007814:Larva / Q000821:virology; D019251:Nucleocapsid / Q000235:genetics*; D017924:Nucleopolyhedroviruses / Q000235:genetics*; D018411:Spodoptera / Q000821:virology*; D014764:Viral Proteins / Q000235:genetics; D014771:Virion / Q000235:genetics*; D014779:Virus Replication / Q000235:genetics
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins