Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9289416 | Virus Research | 2005 | 8 Pages |
Abstract
Defective viruses, not transmissible alone, increase the transmissibility of complete genotypes in natural populations of Spodoptera frugiperda multicapsid nucleopolyhedrovirus (SfMNPV). The defective phenotype is associated with a 15Â kb deletion, which includes the pif (per os infectivity factor) gene. The sequence of a 2.4Â kb fragment that includes pif was determined. Multiple transcripts encompassing pif were detected by Northern blot analysis. RT-PCR and nuclease protection analysis demonstrated the presence of run-through transcripts starting upstream of pif. A 2.0Â kb messenger started from a CTAAG promoter motif located 11Â nt upstream of the pif start codon, and ended 450Â nt downstream from the pif stop codon. This pif mRNA included a small downstream ORF (homologous to Se37). A transcript of 0.8Â kb was detected that may correspond to a specific transcript from this small ORF. This transcript would start at a late consensus motif internal to pif coding sequences, ending at the same polyadenylation signal as the pif transcript. These transcription features resemble those of pif transcription in Spodoptera littoralis NPV, although the genomic location of pif is not equivalent in the two viruses. SfMNPV pif can encode a protein of 529 amino acids, closely related to Spodoptera exigua MNPV PIF.
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Virology
Authors
Oihane Simón, SerafÃn Gutiérrez, Trevor Williams, Primitivo Caballero, Miguel López-Ferber,