Nucleotide sequence and transcriptional analysis of the gp41 gene of Spodoptera frugiperda nuclear polyhedrosis virus.

The Spodoptera frugiperda multiple nucleocapsid nuclear polyhedrosis virus (SfMNPV) gp41 structural protein gene was located in the 1.9 kbp EcoRI-S fragment and sequenced. An open reading frame (ORF) of 999 nucleotides was detected that encoded a protein of 332 amino acids. The gp41 gene transcript was detected after 12 h post-infection (p.i.) and remained detectable at 48 h p.i. Two major mRNAs, about 1.6 and 2.8 kb in length, were determined by Northern blot analysis. Primer extension analysis demonstrated that the gp41 gene promoter region contains three transcription start sites. Two of the gp41 gene transcription start sites were located at -42 and -41 nucleotides from the ATG translation start codon within a consensus late transcription start site (TAAG) and another transcription start site was located at -140 nucleotides from the ATG translation start codon for which no consensus motif has been determined. Comparison of SfMNPV gp41 nucleotide and amino acid sequences with the gp41 genes from Autographa californica, Bombyx mori, and Helicoverpa zea NPVs showed 60% homology of nucleotide sequences and 70% similarity of amino acid sequences.