Nucleotide sequence and transcriptional analysis of the p10 gene of Spodoptera exigua nuclear polyhedrosis virus

Abstract

The p10 gene of Spodoptera exigua multiple nuclear polyhedrosis virus (SeMNPV) was localized on the XbaI fragment H (5.1 kb) of the physical map of the viral genome. The coding sequence of the SeMNPV p10 gene is 264 nucleotides (nt) long corresponding to a predicted protein of 88 amino acids with an MHF of 9607. The SeMNPV p10 protein showed only limited amino acid identity (39% and 26%, respectively) to those of Orgyia pseudotsugata MNPV (OpMNPV) and Autographa californica MNPV (AcMNPV) and thus appears less conserved than other viral proteins. The SeMNPV p10 gene was expressed by a transcript of approximately 450 nt, which started in the conserved baculovirus late gene promoter motif TAAG. The leader of the SeMNPV p10 transcript was AT-rich (92%) and at 36 nt was the shortest leader of all baculovirus major late genes reported so far. The SeMPNV p10 transcript terminated 6 nt downstream from a putative poly(A) signal sequence (AATAAA); the latter was 61 nt downstream of the translational stop codon TAA. Upstream and downstream of the p10 gene, partial putative ORFs were found that showed significant amino acid sequence identity to the baculovirus p26 and p74 proteins. It is concluded that the region of SeMNPV DNA containing the p10 gene is collinear with the corresponding regions in the AcMNPV and OpMNPV genomes.