Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) gp41 gene is 993 bp long and the protein encoded by this gene has 6-66% amino acid identities with other known baculovirus GP41 proteins. Slgp41 transcripts were detected from 12 to 96 h post-infection (p.i.) and the mRNA start site was mapped within a consensus baculovirus late promoter sequence (ATAAG). Western blot analysis of extracts from SpltMNPV-infected S. litura cells detected a 41 kDa protein, and this protein was present in the nucleus of infected cells from 12 to 96 h p.i., whereas in the cytoplasm from 24 to 96 h p.i. Structural localization confirmed that SlGP41 is associated with the envelope of occlusion-derived virus (ODV). Lectin-binding assay showed that three lectins erythrina cristaglli lectin (ECL), lycopersicon esculentum lectin (LEL), and bandeiraea simlicifolia lectin (BSL) recognizing N-acetylglucosamine were specifically bound to SlGP41. It was proposed that SlGP41 is an O-glycoprotein.