Summary auto-generated
Researchers identified and characterized the p10 gene of Spodoptera littoralis nucleopolyhedrovirus (SpliMNPV), a virus that infects lepidopteran insects and may serve as a biological pesticide. The SpliMNPV p10 gene consists of 315 nucleotides encoding a 104-amino acid protein with a molecular weight of 11,130 Da—the longest p10 gene identified in baculoviruses to date. Sequence analysis revealed the protein is most closely related to Spodoptera exigua MNPV p10 (49% amino acid identity) and most distant from Autographa californica MNPV p10 (20% identity). The predicted secondary structure shows an extended alpha-helical domain with high probability of forming a large coiled-coil structure. Northern blot analysis detected a major p10 mRNA transcript of approximately 1,500 nucleotides, with primer extension mapping revealing three transcription start sites at a conserved TAAG promoter motif. Notably, SpliMNPV's p10 gene organization differs significantly from other baculoviruses: instead of being flanked by p26 and p74 genes, it is adjacent to a unique 945-bp open reading frame (ORF945) downstream and a 552-bp upstream ORF (ORF552) that resembles the SeMNPV xb187 gene. This represents a distinctly different genomic arrangement compared to previously characterized baculoviruses.
Key findings
- SpliMNPV p10 is the longest baculoviral p10 gene identified (315 nt, encoding 104 amino acids), featuring an extended coiled-coil structure with ten heptad repeats
- Unique gene organization with ORF552 upstream and ORF945 downstream of p10, differing from the typical p26-p10-p74 cluster found in other baculoviruses
- Three adjacent p10 transcription start sites mapped to the TAAG late promoter motif, with major transcript size of ~1,500 nucleotides detected at late infection stages (48-120 hours post-infection)
- Phylogenetic analysis shows SpliMNPV p10 is most closely related to Spodoptera exigua MNPV p10 (49% amino acid identity) and most distant from Autographa californica MNPV p10 (20% identity)
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
The p10 gene of the Spodoptera littoralis (Spli) multicapsid nucleopolyhedrovirus (MNPV) was identified. With a coding sequence of 315 nucleotides (nt), corresponding to a protein of 104 amino acids, the SpliMNPV p10 gene is the longest p10 gene known. This gene codes for a putative protein with an Mr of 11130 and was found to be most closely related to the Spodoptera exigua (Se) MNPV p10 (49.4% amino acid identity) and most distant from the Autographa californica (Ac) MNPV p10 (20.0% amino acid identity). Characterization of the protein's secondary structure and a comparison with other p10 protein species suggested that this p10 has an extended alpha-helical domain with high probability of forming a large coiled-coil structure. The p10 mRNA was about 1500 nt long, as determined by Northern blot analysis. Primer extension assay mapped three transcription start sites to a conserved baculovirus late promoter motif, TAAG. In the SpliMNPV genome, the p10 gene is not flanked by genes similar to p26 and p74, as found in SeMNPV, AcMNPV, Choristoneura fumiferana MNPV and Orgyia pseudotsugata MNPV. Instead, an open reading frame (ORF) of 945 bp is located downstream from the p10 gene and is followed by another ORF in opposite orientation, encoding the p74 protein. Upstream of the p10 sequences, an ORF of 552 bp was identified that potentially encodes a 184 amino acid protein of Mr 20925, which showed 52.2% identity with the encoded product of the SeMNPV xb187 gene.